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A178087 G.f. satisfies: A(x) = Sum_{n>=0} x^n * Product_{k=1..n} A(k*x). 2
1, 1, 2, 6, 25, 141, 1071, 11011, 154739, 3005187, 81434048, 3101253384, 166823865867, 12719913809811, 1378095292930494, 212524751143894194, 46713381928627546015, 14648866052370410611923, 6558913185973371123604314, 4195585528812861561212654010 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Paul D. Hanna, Table of n, a(n) for n = 0..60

EXAMPLE

G.f.: A(x) = 1 + x + 2*x^2 + 6*x^3 + 25*x^4 + 141*x^5 +...

where

A(x) = 1 + x*A(x) + x^2*A(x)*A(2*x) + x^3*A(x)*A(2*x)*A(3*x) + x^4*A(x)*A(2*x)*A(3*x)*A(4*x) + x^5*A(x)*A(2*x)*A(3*x)*A(4*x)*A(5*x) +...

PROG

(PARI) {a(n)=local(A=1+x); for(i=1, n, A=1+sum(m=1, n, x^m*prod(k=1, m, subst(A, x, k*x+x*O(x^n))))); polcoeff(A, n)}

for(n=0, 20, print1(a(n), ", "))

CROSSREFS

Cf. A230317.

Sequence in context: A007815 A195259 A292748 * A109286 A009466 A348067

Adjacent sequences:  A178084 A178085 A178086 * A178088 A178089 A178090

KEYWORD

nonn

AUTHOR

Paul D. Hanna, May 19 2010

STATUS

approved

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Last modified May 22 00:01 EDT 2022. Contains 353930 sequences. (Running on oeis4.)