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A112808 Expansion of solution of functional equation. 0
1, 1, 2, 5, 14, 43, 142, 495, 1794, 6683, 25388, 97852, 381406, 1500317, 5947798, 23739795, 95326150, 384845581, 1561220986, 6361205709, 26021379044, 106826116871, 439987835410, 1817594141822, 7529012424286, 31265738342993 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..25.

FORMULA

Given g.f. A(x), then series reversion of B(x)=x*A(x^3) is -B(-x).

Given g.f. A(x), then y=x*A(x^3) satisfies y=x+(xy)^2/(1-(xy)^6).

PROG

(PARI) {a(n)=local(A); if(n<0, 0, A=x+O(x^4); for(k=1, n, A=x+subst(x^2/(1-x^6), x, x*A)); polcoeff(A, 3*n+1))}

CROSSREFS

Sequence in context: A123020 A005317 A126566 * A088927 A110489 A005425

Adjacent sequences:  A112805 A112806 A112807 * A112809 A112810 A112811

KEYWORD

nonn

AUTHOR

Michael Somos, Sep 20 2005

STATUS

approved

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Last modified May 9 19:07 EDT 2021. Contains 343746 sequences. (Running on oeis4.)