cp's OEIS Frontend

A155811 a(n) = [x^(n+1)*y] exp( Sum_{m>=1} (2^m + y)^m * x^m/m ), in which the coefficients of x^n*y^k are integer for n>=k>=0.

%I A155811 #2 Mar 30 2012 18:37:16
%S A155811 1,6,82,4452,1074934,1082704500,4411700155252,72146891831948808,
%T A155811 4724816968764733073446,1238218148763614236043117508,
%U A155811 1298203457233136135837147642852956
%N A155811 a(n) = [x^(n+1)*y] exp( Sum_{m>=1} (2^m + y)^m * x^m/m ), in which the coefficients of x^n*y^k are integer for n>=k>=0.
%F A155811 Column 1 of triangle A155810.
%o A155811 (PARI) {a(n)=polcoeff(polcoeff(exp(sum(m=1,n+1,(2^m+y)^m*x^m/m)+x*O(x^(n+1))),n+1,x),1,y)}
%Y A155811 Cf. A155810.
%K A155811 nonn
%O A155811 0,2
%A A155811 _Paul D. Hanna_, Feb 04 2009