Primality tests normalized on GetOrComputePrimality. CofactorIsPrime added to factoring results for reuse in other places.

PerfectNumbers.Core/FactorEntry.cs

@@ -1,8 +1,9 @@
 namespace PerfectNumbers.Core
 {
-    public readonly struct FactorEntry(ulong value, int exponent)
+    public readonly struct FactorEntry(ulong value, int exponent, bool isPrime)
     {
         public readonly ulong Value = value;
-        public readonly int Exponent = exponent;
+		public readonly int Exponent = exponent;
+		public readonly bool CofactorIsPrime = isPrime;
     }
 }