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A063900
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Numbers k such that sum of proper divisors or aliquot parts of k^2 (excluding 1) is a square, or A048050(k^2) is a square.
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1
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866, 9271, 18167, 30887, 39959, 114607, 119279, 129911, 153631, 239111, 343207, 517591, 582583, 602159, 607340, 1202282, 1397863, 1729999, 1920647, 2533183, 2547119, 2558183, 5740127, 7122959, 9379871, 10218407, 10891103, 13549399
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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chowla[n_] := DivisorSigma[1, n] - n - 1; aQ[n_] := IntegerQ@Sqrt@chowla[n^2]; Select[Range[10^6], aQ] (* Amiram Eldar, Aug 30 2019 *)
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PROG
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(PARI) s(n)=sigma(n)-n-1;
for(n=1, 10^8, if(issquare(s(n^2)), print(n)))
(PARI) s(n)=sigma(n) - n - 1
{ n=0; for (m=1, 10^9, if(issquare(s(m^2)), write("b063900.txt", n++, " ", m); if (n==55, break)) ) } \\ Harry J. Smith, Sep 02 2009
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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