cp's OEIS Frontend

A168590 G.f.: exp( Sum_{n>=1} A168591(n)*x^n/n ), where A168591(n) = sum of the n-th power of the trinomial coefficients in row n of triangle A027907.

%I A168590 #2 Mar 30 2012 18:37:20
%S A168590 1,3,14,310,71399,153056789,2826352872319,445742192193898313,
%T A168590 602479884829000885595175,7000510736697461064666950774905,
%U A168590 701725717683874683612335083605682943282
%N A168590 G.f.: exp( Sum_{n>=1} A168591(n)*x^n/n ), where A168591(n) = sum of the n-th power of the trinomial coefficients in row n of triangle A027907.
%e A168590 G.f.: A(x) = 1 + 3*x + 14*x^2 + 310*x^3 + 71399*x^4 +...
%e A168590 log(A(x)) = 3*x + 19*x^2/2 + 831*x^3/3 + 281907*x^4/4 +...+ A168591(n)*x^n/n +...
%o A168590 (PARI) {a(n)=if(n==0,1,polcoeff(exp(sum(m=1,n,sum(k=0,2*m,polcoeff((1+x+x^2)^m,k)^m)*x^m/m) +x*O(x^n)),n))}
%Y A168590 Cf. A168591, A168592, A168593, A027907.
%K A168590 nonn
%O A168590 0,2
%A A168590 _Paul D. Hanna_, Dec 01 2009