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A065741
Largest square <= sum of squares of divisors of n.
12
1, 4, 9, 16, 25, 49, 49, 81, 81, 121, 121, 196, 169, 225, 256, 324, 289, 441, 361, 529, 484, 576, 529, 841, 625, 841, 784, 1024, 841, 1296, 961, 1296, 1156, 1444, 1296, 1849, 1369, 1764, 1681, 2209, 1681, 2500, 1849, 2500, 2304, 2601, 2209, 3364, 2401
OFFSET
1,2
LINKS
FORMULA
a(n) = A048760(A001157(n)).
MATHEMATICA
Table[Floor[Sqrt[DivisorSigma[2, w]]//N]^2, {w, 1, 100}]
PROG
(PARI) sigma2(n)= { local(d, s=0); d=divisors(n); for(i=1, length(d), s+=d[i]^2); return(s) } { for (n=1, 1000, a=sqrtint(sigma2(n))^2; write("b065741.txt", n, " ", a) ) } \\ Harry J. Smith, Oct 29 2009
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Labos Elemer, Nov 15 2001
STATUS
approved