# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a346770
Showing 1-1 of 1

%I A346770 #19 Aug 03 2021 02:14:11
%S A346770 1,-1,-1,-1,0,0,3,1,4,2,3,-5,1,-13,-5,-13,-6,-22,12,-12,35,17,59,11,
%T A346770 101,-1,81,-35,45,-165,29,-311,-69,-383,-57,-501,181,-501,425,-191,
%U A346770 990,-70,1844,64,2305,183,2625,-951,2897,-2701,1845,-4851,664,-8824,670,-12366,269,-14137,2884
%N A346770 Expansion of g.f. Product_{k>=1} (1 - x^k)^phi(k), where phi() is the Euler totient function (A000010).
%H A346770 Seiichi Manyama, <a href="/A346770/b346770.txt">Table of n, a(n) for n = 0..10000</a>
%F A346770 G.f.: exp(-Sum_{k>=1} A057660(k) * x^k/k).
%F A346770 a(0) = 1, a(n) = -(1/n) * Sum_{k=1..n} A057660(k) * a(n-k) for n > 0.
%o A346770 (PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, (1-x^k)^eulerphi(k)))
%o A346770 (PARI) N=66; x='x+O('x^N); Vec(exp(-sum(k=1, N, sigma(k^2, 2)/sigma(k^2)*x^k/k)))
%Y A346770 Convolution inverse of A061255.
%Y A346770 Cf. A000010, A057660, A293116, A299069.
%K A346770 sign
%O A346770 0,7
%A A346770 _Seiichi Manyama_, Aug 02 2021

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE