A232557 Square numbers whose sum of proper square divisors is also square greater than 1.

900, 4900, 10404, 79524, 81796, 417316, 532900, 846400, 1542564, 2464900, 3232804, 3334276, 3496900, 12432676, 43850884, 50836900, 51811204, 71470116, 107453956, 236975236, 253892356, 432889636, 544102276, 864948100, 1192597156, 1450543396

Offset: 1

Author

Antonio Roldán, Nov 26 2013

Keywords

• nonn

Examples

			10404 = 102^2 is a square number. Sum of proper square divisor of 10404 is 2601 + 1156 + 289 + 36 + 9 + 4 + 1 = 4096 = 64^2.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1000

Crossrefs

Subsequence of A232556.

Cf. A035316, A232554, A232555.

Programs

Mathematica

f[p_, e_] := (p^(2*(1 + Floor[e/2])) - 1)/(p^2 - 1); A035316[1] = 1; A035316[n_] := Times @@ f @@@ FactorInteger[n]; sqQ[n_] := n>1 && IntegerQ[Sqrt[n]];
Select[Range[40000]^2, sqQ[A035316[#] - #]&] (* Amiram Eldar, Aug 12 2023 *)

PARI

{for(n=1,10^5,m=n*n;k=sumdiv(m,d,d*issquare(d)*(d>1,print(m)))}