A187444 A trisection of A001405 (central binomial coefficients): binomial(3n+2,floor((3n+2)/2))/2, n>=0.

1, 5, 35, 231, 1716, 12155, 92378, 676039, 5200300, 38779380, 300540195, 2268783825, 17672631900, 134564468610, 1052049481860, 8061900920775, 63205303218876, 486734856412028, 3824345300380220, 29566145391215356, 232714176627630544, 1804857108504066435

Offset

0,2

Comments

For the trisection of sequences see a comment and a reference under A187357.

Links

Table of n, a(n) for n=0..21.

Formula

a(n) = binomial(3*n+2,floor((3*n+2)/2))/2, n>=0.

O.g.f.: G1(x^2) + x*G2(x^2), with G1(x) and G2(x) the o.g.f.s of A187364 and A187366, respectively.

Prog

(PARI) vector(30, n, n--; binomial(3*n+2, (3*n+2)\2)/2) \\ Michel Marcus, Jun 11 2015

Crossrefs

Cf. A187442: binomial(3*n,floor(3*n/2)), A187443: binomial(3*n+1,floor((3*n+1)/2)).

Sequence in context: A024062 A180250 A002074 * A166176 A154780 A007995

Adjacent sequences: A187441 A187442 A187443 * A187445 A187446 A187447

Keyword

nonn,easy

Author

Wolfdieter Lang, Mar 10 2011

Status

approved