A195259 G.f.: A(x) = 1 + Sum_{n>=1} x^n*A(x)^(3^(n-1)).

1, 1, 2, 6, 25, 138, 1036, 11270, 194105, 5600367, 275058868, 22805688464, 3173290832407, 739292604671606, 288039050041591288, 188101949731185856592, 205677982188934721693289, 377993929252274297946197815, 1165828413037318706712871579130

Offset

0,3

Links

Table of n, a(n) for n=0..18.

Example

G.f.: A(x) = 1 + x + 2*x^2 + 6*x^3 + 25*x^4 + 138*x^5 + 1036*x^6 +...
where
A(x) = 1 + x*A(x) + x^2*A(x)^3 + x^3*A(x)^9 + x^4*A(x)^27 + x^5*A(x)^81 +...
Related expansions begin:
A(x)^3 = 1 + 3*x + 9*x^2 + 31*x^3 + 129*x^4 + 666*x^5 + 4499*x^6 +...
A(x)^9 = 1 + 9*x + 54*x^2 + 282*x^3 + 1431*x^4 + 7560*x^5 + 44568*x^6 +...
A(x)^27 = 1 + 27*x + 405*x^2 + 4491*x^3 + 41391*x^4 + 338580*x^5 + 2571669*x^6 +...

Prog

(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(k=1, n, A=1+sum(j=1, n, x^j*A^(3^(j-1)))); polcoeff(A, n)}

Crossrefs

Cf. A195260, A107589, A159609.

Sequence in context: A197772 A135881 A007815 * A292748 A178087 A109286

Adjacent sequences: A195256 A195257 A195258 * A195260 A195261 A195262

Keyword

nonn

Author

Paul D. Hanna, Sep 13 2011

Status

approved