cp's OEIS Frontend

A242649 Dirichlet g.f.: Product_{n>=2} 1/(1-1/n^s)^d(n), where d(n) = A000005(n) is the number of divisors of n.

%I A242649 #23 Nov 24 2023 12:12:20
%S A242649 1,2,2,6,2,8,2,14,6,8,2,26,2,8,8,33,2,26,2,26,8,8,2,72,6,8,14,26,2,40,
%T A242649 2,70,8,8,8,95,2,8,8,72,2,40,2,26,26,8,2,184,6,26,8,26,2,72,8,72,8,8,
%U A242649 2,148,2,8,26,149,8,40,2,26,8,40,2,282,2,8,26
%N A242649 Dirichlet g.f.: Product_{n>=2} 1/(1-1/n^s)^d(n), where d(n) = A000005(n) is the number of divisors of n.
%H A242649 Antti Karttunen, <a href="/A242649/b242649.txt">Table of n, a(n) for n = 1..10001</a>
%o A242649 (PARI) \\ Based on Michael Somos's code for A007896
%o A242649 n=101;
%o A242649 v = vector(n, k, k==1);
%o A242649 for(k=2, n, m = #digits(n, k) - 1; A = (1 - x)^ -(sigma(k,0)) + x * O(x^m); w = vector(n); for(i=0, m, w[k^i] = polcoeff(A, i)); v = dirmul(v, w));
%o A242649 v
%Y A242649 Cf. A000005, A007896, A050367, A242649.
%K A242649 nonn
%O A242649 1,2
%A A242649 _N. J. A. Sloane_, May 26 2014