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A161637 G.f.: A(x) = exp( Sum_{n>=1} x^n/(1 - 2^(n^2)*x^n)/n ). 0

%I #2 Mar 30 2012 18:37:17

%S 1,1,3,7,25,49,421,589,20051,109571,6897743,7158695,12593657691,

%T 12622726251,80459328159219,305712703088131,2306380162670320841,

%U 2307152558777717417,269444164561317686825525,269453394201317013516237

%N G.f.: A(x) = exp( Sum_{n>=1} x^n/(1 - 2^(n^2)*x^n)/n ).

%e G.f.: A(x) = 1 + x + 3*x^2 + 7*x^3 + 25*x^4 + 49*x^5 +...

%e log(A(x)) = x/(1-2*x) + x^2/(1-2^4*x^2)/2 + x^3/(1-2^9*x^3)/3 +...

%o (PARI) {a(n)=if(n==0, 1, polcoeff(exp(sum(k=1, n, x^k/(1-2^(k^2)*x^k +x*O(x^n))/k)), n))}

%Y Cf. A158097.

%K nonn

%O 0,3

%A _Paul D. Hanna_, Jun 18 2009

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Last modified September 5 22:34 EDT 2024. Contains 375701 sequences. (Running on oeis4.)