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A141203 G.f. satisfies: A(x - x*B(x)) = x where B(x) = (A(x) - A(-x))/2, the odd bisection of A(x). 1
1, 1, 2, 7, 26, 124, 596, 3365, 18954, 120242, 760140, 5281436, 36617556, 274624708, 2059397032, 16520347463, 132773992954, 1132184343204, 9689336590700, 87424470404886, 792807348829740, 7541745922428356, 72187384283011000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) == 1 (mod 2) iff n = 2^k for k>=0.

LINKS

Paul D. Hanna, Table of n, a(n) for n = 1..300

EXAMPLE

G.f.: A(x) = x + x^2 + 2*x^3 + 7*x^4 + 26*x^5 + 124*x^6 + 596*x^7 +...

The series reversion of A(x) = x - x*[A(x) - A(-x)]/2, thus:

A(x - x^2 - 2*x^4 - 26*x^6 - 596*x^8 - 18954*x^10 -...) = x.

PROG

(PARI) {a(n)=local(A=x+x^2); for(i=0, n, A=serreverse(x-x/2*(A-subst(A, x, -x+x*O(x^n))))) ; polcoeff(A, n)}

CROSSREFS

Sequence in context: A302691 A081566 A213094 * A096803 A036757 A300049

Adjacent sequences:  A141200 A141201 A141202 * A141204 A141205 A141206

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jun 13 2008

STATUS

approved

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Last modified June 19 23:39 EDT 2019. Contains 324222 sequences. (Running on oeis4.)