A213905 G.f. satisfies: A(x) = x^2+x^3 + A(A(x)).

1, 1, 1, 2, 4, 9, 20, 47, 112, 274, 678, 1702, 4314, 11039, 28460, 73875, 192884, 506251, 1334899, 3534591, 9394196, 25052866, 67019457, 179793858, 483591479, 1303836901, 3523141231, 9539570474, 25879559378, 70332798052, 191461351903, 522012186777, 1425327940690

Offset

2,4

Links

Paul D. Hanna, Table of n, a(n) for n = 2..301

Example

G.f.: A(x) = x^2 + x^3 + x^4 + 2*x^5 + 4*x^6 + 9*x^7 + 20*x^8 + 47*x^9 +...
where
A(A(x)) = x^4 + 2*x^5 + 4*x^6 + 9*x^7 + 20*x^8 + 47*x^9 + 112*x^10 +...

Prog

(PARI) {a(n)=local(A=x^2+x^3); for(i=1, n, A = x^2 + x^3 + subst(A, x, A+x*O(x^n))); polcoeff(A, n)}
for(n=2, 40, print1(a(n), ", "))

Crossrefs

Cf. A213906.

Sequence in context: A196244 A035084 A363557 * A058385 A058386 A095980

Adjacent sequences: A213902 A213903 A213904 * A213906 A213907 A213908

Keyword

nonn

Author

Paul D. Hanna, Jun 24 2012

Status

approved