A071326 - OEIS

%I #10 Nov 17 2017 20:33:15

%S 0,0,0,4,0,0,0,4,9,0,0,4,0,0,0,20,0,9,0,4,0,0,0,4,25,0,9,4,0,0,0,20,0,

%T 0,0,49,0,0,0,4,0,0,0,4,9,0,0,20,49,25,0,4,0,9,0,4,0,0,0,4,0,0,9,84,0,

%U 0,0,4,0,0,0,49,0,0,25,4,0,0,0,20,90,0,0,4,0,0,0,4,0,9,0,4,0,0,0,20,0,49,9,129

%N Sum of squares > 1 dividing n.

%H Antti Karttunen, <a href="/A071326/b071326.txt">Table of n, a(n) for n = 1..16384</a>

%F a(n) = A035316(n)-1.

%F Sum_{d|n, d>1} A010052(d). - _Antti Karttunen_, Nov 17 2017

%t Array[DivisorSum[#, # &, IntegerQ@ Sqrt@ # &] - 1 &, 100] (* _Michael De Vlieger_, Nov 17 2017 *)

%o (PARI) A071326(n) = sumdiv(n,d,(d>1)*issquare(d)*d); \\ _Antti Karttunen_, Nov 17 2017

%Y Cf. A000203, A010052, A071325, A071327.

%Y One less than A035316.

%K nonn

%O 1,4

%A _Reinhard Zumkeller_, May 18 2002

%E More terms from _Antti Karttunen_, Nov 17 2017