RE: [PrimeNumbers] Squarerooting
> Observed heuristically, if you sum the digits of a squareIndeed. It's the quadratic residue test with modulus 9. It's subsumed
> recursively to a
> single digit, the squares will sum to 1, 4, 7, or 9 only. For
> example 5329-->
> Also the square sums have roots with specific sums:
> 1 squares have roots that sum to 1 or 8
> 4 squares have roots that sum to 2 or 7
> 7 squares have roots that sum to 4 or 5
> 9 squares have roots that sum to 3, 6 or 9
> I think this is equivalent to one of the methods shown
> earlier and only rules out some numbers.
in the mod 63 test I gave and it's equivalent in the other proposals.