A069293 - OEIS

%I #18 Apr 04 2020 21:25:03

%S 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,5,1,1,1,5,1,1,1,5,1,1,1,5,1,1,1,5,1,1,

%T 1,5,1,1,1,5,1,1,1,5,1,1,1,5,1,1,1,5,1,1,1,5,1,1,1,5,1,1,1,5,1,1,1,5,

%U 1,1,1,5,1,1,1,5,1,1,1,5,10,1,1,5,1,1,1,5,1,10,1,5,1,1,1,5,1,1,10,5,1,1,1,5,1

%N Sum of square divisors of n <= sqrt(n).

%H Antti Karttunen, <a href="/A069293/b069293.txt">Table of n, a(n) for n = 1..16384</a>

%H <a href="/index/Su#sums_of_divisors">Index entries for sequences related to sums of divisors</a>

%F G.f.: Sum_{k>=1} k^2 * x^(k^4) / (1 - x^(k^2)). - _Ilya Gutkovskiy_, Apr 04 2020

%t Table[DivisorSum[n, # &, And[IntegerQ@ Sqrt@ #, # <= Sqrt@ n] &], {n, 105}] (* _Michael De Vlieger_, Nov 20 2017 *)

%o (PARI) A069293(n) = sumdiv(n, d, (issquare(d)&&((d^2)<=n))*d); \\ _Antti Karttunen_, Nov 20 2017

%Y Cf. A000188, A035316, A046951, A069290, A069291, A069292.

%K nonn

%O 1,16

%A _Reinhard Zumkeller_, Mar 14 2002

%E More terms from _Antti Karttunen_, Nov 20 2017