A216586 G.f.: exp( Sum_{n>=1} A002426(n)/2 * A002426(n) * x^n/n ), where A002426 is the central binomial coefficients and A002426 is the central trinomial coefficients.

1, 1, 5, 28, 202, 1579, 13375, 118858, 1098458, 10453452, 101872926, 1012109860, 10218226307, 104570617520, 1082633236498, 11321654913838, 119438468577559, 1269787015989428, 13592294300856138, 146390465351654178, 1585337895099162317, 17253991887494062080

Offset: 0

Author

Paul D. Hanna, Sep 09 2012

Keywords

• nonn

Examples

			G.f.: A(x) = 1 + x + 5*x^2 + 28*x^3 + 202*x^4 + 1579*x^5 + 13375*x^6 +...
such that
log(A(x)) = 1*1*x + 3*3*x^2/2 + 10*7*x^3/3 + 35*19*x^4/4 + 126*51*x^5/5 + 462*141*x^6/6 +...+ A001700(n)*A002426(n)*x^n/n +...
		

Crossrefs

Cf. A216585, A002426, A001700, A000984.

Programs

PARI

{a(n)=polcoeff(exp(sum(m=1,n+1,binomial(2*m,m)/2*polcoeff((1+x+x^2)^m,m)*x^m/m+x*O(x^n))),n)}
for(n=0,30,print1(a(n),", "))

Formula

Self-convolution yields A216585.