A195260 G.f.: A(x) = 1 + Sum_{n>=1} x^n*A(x)^(3^n).

1, 1, 4, 25, 200, 1948, 23293, 366698, 8669713, 354287410, 26296911212, 3452678049185, 778932197922145, 297680194679224221, 192063113715788790619, 208413189299565620902495, 381159431868835826320370849, 1171978295935406653806412222411

Offset

0,3

Links

Table of n, a(n) for n=0..17.

Example

 G.f.: A(x) = 1 + x + 4*x^2 + 25*x^3 + 200*x^4 + 1948*x^5 + 23293*x^6 +...
where
A(x) = 1 + x*A(x)^3 + x^2*A(x)^9 + x^3*A(x)^27 + x^4*A(x)^81 +...
Related expansions begin:
A(x)^3 = 1 + 3*x + 15*x^2 + 100*x^3 + 810*x^4 + 7767*x^5 + 89506*x^6 +...
A(x)^9 = 1 + 9*x + 72*x^2 + 597*x^3 + 5310*x^4 + 51606*x^5 + 563469*x^6 +...
A(x)^27 = 1 + 27*x + 459*x^2 + 6408*x^3 + 81216*x^4 + 984501*x^5 + 11824992*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))); polcoeff(A, n)}

Crossrefs

Cf. A195259, A107589, A159609.

Sequence in context: A215505 A182304 A060910 * A254796 A347585 A088159

Adjacent sequences: A195257 A195258 A195259 * A195261 A195262 A195263

Keyword

nonn

Author

Paul D. Hanna, Sep 13 2011

Status

approved