A307607 - OEIS

%I #11 Apr 20 2019 03:02:05

%S 1,5,10,37,26,122,50,293,172,330,122,1306,170,642,710,2341,290,2876,

%T 362,3562,1382,1578,530,13082,1276,2202,3088,6946,842,12822,962,18725,

%U 3398,3762,3750,37756,1370,4698,4742,35818,1682,25014,1850,17098,17072,6882

%N a(n) = 1 + Sum_{d|n, d > 1} d^2*a(n/d).

%H Seiichi Manyama, <a href="/A307607/b307607.txt">Table of n, a(n) for n = 1..10000</a>

%F L.g.f.: -log(Product_{k>=1} (1 - x^k)^(k*A074206(k))) = Sum_{n>=1} a(n)*x^n/n.

%t a[n_] := a[n] = 1 + DivisorSum[n, #^2 a[n/#] &, # > 1 &]; Table[a[n], {n, 1, 46}]

%o (PARI) a(n) = 1 + sumdiv(n, d, if (d>1, d^2*a(n/d))); \\ _Michel Marcus_, Apr 20 2019

%Y Cf. A074206, A197953, A307604.

%K nonn

%O 1,2

%A _Ilya Gutkovskiy_, Apr 18 2019