login
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.
1

%I #2 Mar 30 2012 18:37:16

%S 1,6,82,4452,1074934,1082704500,4411700155252,72146891831948808,

%T 4724816968764733073446,1238218148763614236043117508,

%U 1298203457233136135837147642852956

%N 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 Column 1 of triangle A155810.

%o (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 Cf. A155810.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Feb 04 2009