A135864 G.f. A(x) satisfies: A(x) = 1 + 9x*A(x)^(1/3).

1, 9, 27, 0, -81, 243, 0, -2916, 10935, 0, -168399, 682344, 0, -11711385, 49364964, 0, -900438201, 3887490915, 0, -73729998576, 323480165085, 0, -6303914878248, 27978933759300, 0, -556251967191492, 2490404893915293, 0, -50276620111538700, 226626845346291663, 0

Offset

0,2

Links

Table of n, a(n) for n=0..30.

Formula

a(n) = -9^n*binomial(n/3,n)/(2n/3 - 1).

Prog

(PARI) a(n)=9^n*binomial(n/3, n)/(1-2*n/3)

Crossrefs

Cf. A135863, A135866.

Sequence in context: A056409 A056399 A256927 * A074954 A103952 A103955

Adjacent sequences: A135861 A135862 A135863 * A135865 A135866 A135867

Keyword

sign

Author

Paul D. Hanna, Dec 02 2007

Status

approved