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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

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%I A232557 #15 Aug 12 2023 04:37:52
%S A232557 900,4900,10404,79524,81796,417316,532900,846400,1542564,2464900,
%T A232557 3232804,3334276,3496900,12432676,43850884,50836900,51811204,71470116,
%U A232557 107453956,236975236,253892356,432889636,544102276,864948100,1192597156,1450543396
%N A232557 Square numbers whose sum of proper square divisors is also square greater than 1.
%H A232557 Amiram Eldar, <a href="/A232557/b232557.txt">Table of n, a(n) for n = 1..1000</a>
%e A232557 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.
%t A232557 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]];
%t A232557 Select[Range[40000]^2, sqQ[A035316[#] - #]&] (* _Amiram Eldar_, Aug 12 2023 *)
%o A232557 (PARI) {for(n=1,10^5,m=n*n;k=sumdiv(m,d,d*issquare(d)*(d<m));if(issquare(k)&&k>>1,print(m)))}
%Y A232557 Subsequence of A232556.
%Y A232557 Cf. A035316, A232554, A232555.
%K A232557 nonn
%O A232557 1,1
%A A232557 _Antonio Roldán_, Nov 26 2013