Use precomputed small prime squares in GPU sieve

PerfectNumbers.Core/Gpu/Kernels/PrimeTesterKernels.cs

@@ -7,7 +7,12 @@ namespace PerfectNumbers.Core.Gpu;
 internal static class PrimeTesterKernels
 {
     // GPU kernel: small-prime sieve only. Returns 1 if passes sieve (probable prime), 0 otherwise.
-    public static void SmallPrimeSieveKernel(Index1D index, ArrayView<ulong> numbers, ArrayView<uint> smallPrimes, ArrayView<byte> results)
+    public static void SmallPrimeSieveKernel(
+        Index1D index,
+        ArrayView<ulong> numbers,
+        ArrayView<uint> smallPrimes,
+        ArrayView<ulong> smallPrimeSquares,
+        ArrayView<byte> results)
     {
         ulong n = numbers[index];
 
@@ -28,7 +33,7 @@ internal static class PrimeTesterKernels
         for (int i = 0; i < length; i++)
         {
             ulong prime = smallPrimes[i];
-            ulong primeSquare = (ulong)prime * prime;
+            ulong primeSquare = smallPrimeSquares[i];
             bool withinRange = primeSquare <= n;
             ulong remainder = n % prime;
             bool divides = remainder == 0UL;