

A187443


A trisection of A001405 (central binomial coefficients): binomial(3n+1,floor((3n+1)/2)), n>=0.


2



1, 6, 35, 252, 1716, 12870, 92378, 705432, 5200300, 40116600, 300540195, 2333606220, 17672631900, 137846528820, 1052049481860, 8233430727600, 63205303218876, 495918532948104, 3824345300380220, 30067266499541040, 232714176627630544, 1832624140942590534, 0
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OFFSET

0,2


COMMENTS

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


LINKS

Table of n, a(n) for n=0..22.


FORMULA

a(n) = binomial(3*n+1,floor((3*n+1)/2)), n>=0.
O.g.f.: 3!*x*G2(x^2) + G1(x^2), with G2(x) and G1(x) the o.g.f.s of A187365 and A187364, respectively.


CROSSREFS

Cf. A187442: binomial(3n,floor(3n/2)),
A187444: binomial(3n+2,floor((3n+2)/2))/2.
Sequence in context: A145145 A249476 A244267 * A087631 A167579 A030446
Adjacent sequences: A187440 A187441 A187442 * A187444 A187445 A187446


KEYWORD

nonn,easy


AUTHOR

Wolfdieter Lang, Mar 10 2011


STATUS

approved



