No. There was not any reason for that. Test examples added in description.

Added one more test and changed the datatype (int => long) in random tests because of the parameter type in the method ExpandedForm.

Go translation added. Let it go :)

Random tests added.

In C# use, e.g:

int[] a = new[] { 1, 2, 3 };

System.Console.WriteLine($"[{string.Join(", ", a)}]");

Please add one more edge case test in C#:

[Test]
public void Test12() => Assert.AreEqual("[[1, 1], [42, 2500]]", SumSquaredDivisors.listSquared(1, 42));

In C# random tests should generate random numbers of type long since the method EqSumPowDigSol takes a parameter of type long, e.g:

long n = (long)(rnd.NextDouble() * (long.MaxValue));

The pown function can cause an overflow exception, e.g:

pown Int64.MaxValue 2 // => OverflowException

Int64.MaxValue * Int64.MaxValue // => 1

Fixed it with other fork.

Thanks for pointing out this issue. Added necessary import declarations for random tests.