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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, 14226520737620288370, 112186277816662845432, 873065282167813104916
OFFSET
0,2
COMMENTS
For trisection of sequences see a comment and a reference under A187357.
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.
MATHEMATICA
Table[Binomial[3n+1, Floor[(3n+1)/2]], {n, 0, 30}] (* Harvey P. Dale, Jan 13 2021 *)
CROSSREFS
Cf. A187442: binomial(3n,floor(3n/2)), A187444: binomial(3n+2,floor((3n+2)/2))/2.
Cf. A001405.
Sequence in context: A346922 A355381 A244267 * A325115 A087631 A167579
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Mar 10 2011
EXTENSIONS
Corrected and extended by Harvey P. Dale, Jan 13 2021
STATUS
approved