A206179 G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n,k)^3 * 3^k ).

1, 4, 25, 196, 1747, 16996, 175936, 1907224, 21423385, 247515796, 2925668236, 35239199704, 431207470105, 5347823877172, 67093724913313, 850241358959044, 10869754843088962, 140045452765874704, 1816842996684686656, 23716478425653945472, 311314468637807994391

Offset: 0

Author

Paul D. Hanna, Feb 04 2012

Keywords

• nonn

Comments

Logarithmic derivative yields A206180.

Examples

			G.f.: A(x) = 1 + 4*x + 25*x^2 + 196*x^3 + 1747*x^4 + 16996*x^5 +...
where
log(A(x)) = 4*x + 34*x^2/2 + 352*x^3/3 + 3946*x^4/4 + 46744*x^5/5 + 573616*x^6/6 +...+ A206180(n)*x^n/n +...
		

Crossrefs

Cf. A206180, A206177.

Programs

PARI

{a(n)=polcoeff(exp(sum(m=1,n,x^m/m*sum(k=0,m,binomial(m,k)^3*3^k))+x*O(x^n)),n)}
for(n=0,41,print1(a(n),", "))