Find the sum of squares for prime numbers of the form (4k + 1)., C#

Find the sum of squares for prime numbers of the form (4k + 1).

Language: Layout:

//Rextester.Program.Main is the entry point for your code. Don't change it.
//Microsoft (R) Visual C# Compiler version 2.9.0.63208 (958f2354)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            for (int i = 5; i <= 2017; i++)
            {
                if (i % 4 == 1 && IsPrime(i))
                {
                    Console.WriteLine($"Find (4k + 1) number: {i}. Squares: {GetSquares(i)}");
                }
            }
        }
        
        public static Tuple<int, int> GetSquares(int target)
        {
            for (int i = 0; i <= target; i++)
            {
                for (int j = 0; j <= target; j++)
                {
                    var x2 = i * i;
                    var y2 = j * j;
                    if (x2 + y2 == target)
                        return new Tuple<int, int>(i, j);
                }
            }
            return new Tuple<int, int>(-1, -1);
        }
        
        public static bool IsPrime(int target)
        {
            for (int i = 2; i <= target / 2 + 1; i++)
                if (target % i == 0) return false;
             return true;   
        }
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0,38 sec, absolute running time: 0,11 sec, cpu time: 0,11 sec, average memory usage: 16 Mb, average nr of threads: 3, absolute service time: 3,64 sec

Find (4k + 1) number: 5. Squares: (1, 2) Find (4k + 1) number: 13. Squares: (2, 3) Find (4k + 1) number: 17. Squares: (1, 4) Find (4k + 1) number: 29. Squares: (2, 5) Find (4k + 1) number: 37. Squares: (1, 6) Find (4k + 1) number: 41. Squares: (4, 5) Find (4k + 1) number: 53. Squares: (2, 7) Find (4k + 1) number: 61. Squares: (5, 6) Find (4k + 1) number: 73. Squares: (3, 8) Find (4k + 1) number: 89. Squares: (5, 8) Find (4k + 1) number: 97. Squares: (4, 9) Find (4k + 1) number: 101. Squares: (1, 10) Find (4k + 1) number: 109. Squares: (3, 10) Find (4k + 1) number: 113. Squares: (7, 8) Find (4k + 1) number: 137. Squares: (4, 11) Find (4k + 1) number: 149. Squares: (7, 10) Find (4k + 1) number: 157. Squares: (6, 11) Find (4k + 1) number: 173. Squares: (2, 13) Find (4k + 1) number: 181. Squares: (9, 10) Find (4k + 1) number: 193. Squares: (7, 12) Find (4k + 1) number: 197. Squares: (1, 14) Find (4k + 1) number: 229. Squares: (2, 15) Find (4k + 1) number: 233. Squares: (8, 13) Find (4k + 1) number: 241. Squares: (4, 15) Find (4k + 1) number: 257. Squares: (1, 16) Find (4k + 1) number: 269. Squares: (10, 13) Find (4k + 1) number: 277. Squares: (9, 14) Find (4k + 1) number: 281. Squares: (5, 16) Find (4k + 1) number: 293. Squares: (2, 17) Find (4k + 1) number: 313. Squares: (12, 13) Find (4k + 1) number: 317. Squares: (11, 14) Find (4k + 1) number: 337. Squares: (9, 16) Find (4k + 1) number: 349. Squares: (5, 18) Find (4k + 1) number: 353. Squares: (8, 17) Find (4k + 1) number: 373. Squares: (7, 18) Find (4k + 1) number: 389. Squares: (10, 17) Find (4k + 1) number: 397. Squares: (6, 19) Find (4k + 1) number: 401. Squares: (1, 20) Find (4k + 1) number: 409. Squares: (3, 20) Find (4k + 1) number: 421. Squares: (14, 15) Find (4k + 1) number: 433. Squares: (12, 17) Find (4k + 1) number: 449. Squares: (7, 20) Find (4k + 1) number: 457. Squares: (4, 21) Find (4k + 1) number: 461. Squares: (10, 19) Find (4k + 1) number: 509. Squares: (5, 22) Find (4k + 1) number: 521. Squares: (11, 20) Find (4k + 1) number: 541. Squares: (10, 21) Find (4k + 1) number: 557. Squares: (14, 19) Find (4k + 1) number: 569. Squares: (13, 20) Find (4k + 1) number: 577. Squares: (1, 24) Find (4k + 1) number: 593. Squares: (8, 23) Find (4k + 1) number: 601. Squares: (5, 24) Find (4k + 1) number: 613. Squares: (17, 18) Find (4k + 1) number: 617. Squares: (16, 19) Find (4k + 1) number: 641. Squares: (4, 25) Find (4k + 1) number: 653. Squares: (13, 22) Find (4k + 1) number: 661. Squares: (6, 25) Find (4k + 1) number: 673. Squares: (12, 23) Find (4k + 1) number: 677. Squares: (1, 26) Find (4k + 1) number: 701. Squares: (5, 26) Find (4k + 1) number: 709. Squares: (15, 22) Find (4k + 1) number: 733. Squares: (2, 27) Find (4k + 1) number: 757. Squares: (9, 26) Find (4k + 1) number: 761. Squares: (19, 20) Find (4k + 1) number: 769. Squares: (12, 25) Find (4k + 1) number: 773. Squares: (17, 22) Find (4k + 1) number: 797. Squares: (11, 26) Find (4k + 1) number: 809. Squares: (5, 28) Find (4k + 1) number: 821. Squares: (14, 25) Find (4k + 1) number: 829. Squares: (10, 27) Find (4k + 1) number: 853. Squares: (18, 23) Find (4k + 1) number: 857. Squares: (4, 29) Find (4k + 1) number: 877. Squares: (6, 29) Find (4k + 1) number: 881. Squares: (16, 25) Find (4k + 1) number: 929. Squares: (20, 23) Find (4k + 1) number: 937. Squares: (19, 24) Find (4k + 1) number: 941. Squares: (10, 29) Find (4k + 1) number: 953. Squares: (13, 28) Find (4k + 1) number: 977. Squares: (4, 31) Find (4k + 1) number: 997. Squares: (6, 31) Find (4k + 1) number: 1009. Squares: (15, 28) Find (4k + 1) number: 1013. Squares: (22, 23) Find (4k + 1) number: 1021. Squares: (11, 30) Find (4k + 1) number: 1033. Squares: (3, 32) Find (4k + 1) number: 1049. Squares: (5, 32) Find (4k + 1) number: 1061. Squares: (10, 31) Find (4k + 1) number: 1069. Squares: (13, 30) Find (4k + 1) number: 1093. Squares: (2, 33) Find (4k + 1) number: 1097. Squares: (16, 29) Find (4k + 1) number: 1109. Squares: (22, 25) Find (4k + 1) number: 1117. Squares: (21, 26) Find (4k + 1) number: 1129. Squares: (20, 27) Find (4k + 1) number: 1153. Squares: (8, 33) Find (4k + 1) number: 1181. Squares: (5, 34) Find (4k + 1) number: 1193. Squares: (13, 32) Find (4k + 1) number: 1201. Squares: (24, 25) Find (4k + 1) number: 1213. Squares: (22, 27) Find (4k + 1) number: 1217. Squares: (16, 31) Find (4k + 1) number: 1229. Squares: (2, 35) Find (4k + 1) number: 1237. Squares: (9, 34) Find (4k + 1) number: 1249. Squares: (15, 32) Find (4k + 1) number: 1277. Squares: (11, 34) Find (4k + 1) number: 1289. Squares: (8, 35) Find (4k + 1) number: 1297. Squares: (1, 36) Find (4k + 1) number: 1301. Squares: (25, 26) Find (4k + 1) number: 1321. Squares: (5, 36) Find (4k + 1) number: 1361. Squares: (20, 31) Find (4k + 1) number: 1373. Squares: (2, 37) Find (4k + 1) number: 1381. Squares: (15, 34) Find (4k + 1) number: 1409. Squares: (25, 28) Find (4k + 1) number: 1429. Squares: (23, 30) Find (4k + 1) number: 1433. Squares: (8, 37) Find (4k + 1) number: 1453. Squares: (3, 38) Find (4k + 1) number: 1481. Squares: (16, 35) Find (4k + 1) number: 1489. Squares: (20, 33) Find (4k + 1) number: 1493. Squares: (7, 38) Find (4k + 1) number: 1549. Squares: (18, 35) Find (4k + 1) number: 1553. Squares: (23, 32) Find (4k + 1) number: 1597. Squares: (21, 34) Find (4k + 1) number: 1601. Squares: (1, 40) Find (4k + 1) number: 1609. Squares: (3, 40) Find (4k + 1) number: 1613. Squares: (13, 38) Find (4k + 1) number: 1621. Squares: (10, 39) Find (4k + 1) number: 1637. Squares: (26, 31) Find (4k + 1) number: 1657. Squares: (19, 36) Find (4k + 1) number: 1669. Squares: (15, 38) Find (4k + 1) number: 1693. Squares: (18, 37) Find (4k + 1) number: 1697. Squares: (4, 41) Find (4k + 1) number: 1709. Squares: (22, 35) Find (4k + 1) number: 1721. Squares: (11, 40) Find (4k + 1) number: 1733. Squares: (17, 38) Find (4k + 1) number: 1741. Squares: (29, 30) Find (4k + 1) number: 1753. Squares: (27, 32) Find (4k + 1) number: 1777. Squares: (16, 39) Find (4k + 1) number: 1789. Squares: (5, 42) Find (4k + 1) number: 1801. Squares: (24, 35) Find (4k + 1) number: 1861. Squares: (30, 31) Find (4k + 1) number: 1873. Squares: (28, 33) Find (4k + 1) number: 1877. Squares: (14, 41) Find (4k + 1) number: 1889. Squares: (17, 40) Find (4k + 1) number: 1901. Squares: (26, 35) Find (4k + 1) number: 1913. Squares: (8, 43) Find (4k + 1) number: 1933. Squares: (13, 42) Find (4k + 1) number: 1949. Squares: (10, 43) Find (4k + 1) number: 1973. Squares: (23, 38) Find (4k + 1) number: 1993. Squares: (12, 43) Find (4k + 1) number: 1997. Squares: (29, 34) Find (4k + 1) number: 2017. Squares: (9, 44)