A259609 G.f. A(x) satisfies: A'(x)/2 = Series_Reversion( x - x^2*A'(x) - 2*x*A(x) ).

1, 1, 5, 41, 438, 5564, 80237, 1278297, 22108374, 410124999, 8089569676, 168555880750, 3691281132962, 84623035267642, 2024303994864497, 50394612947711173, 1302706707186206332, 34901118404682549804, 967494986526757083191, 27710705833750559374772, 818986747695251513692537

Offset

2,3

Links

Table of n, a(n) for n=2..22.

Formula

a(n) = A259608(n)/n for n>=1.

Example

 G.f.: A(x) = x^2 + x^4 + 5*x^6 + 41*x^8 + 438*x^10 + 5564*x^12 + 80237*x^14 +...
where
A'(x)/2 = x + 2*x^3 + 15*x^5 + 164*x^7 + 2190*x^9 + 33384*x^11 + 561659*x^13 + 10226376*x^15 +...+ A259608(n)*x^(2*n-1) +...

Prog

 (PARI) {a(n)=local(A=x); for(i=0, n, A = serreverse(x - x^2*A - x*intformal(2*A) +x*O(x^(2*n)))); polcoeff(A, 2*n-1)/n}
for(n=1, 25, print1(a(n), ", "))

Crossrefs

Cf. A259608.

Sequence in context: A081215 A218219 A140095 * A323213 A083073 A379879

Adjacent sequences: A259606 A259607 A259608 * A259610 A259611 A259612

Keyword

nonn

Author

Paul D. Hanna, Jul 01 2015

Status

approved