OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..1000
EXAMPLE
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.
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 *)
PROG
(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)))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Antonio Roldán, Nov 26 2013
STATUS
approved