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A187442
A trisection of A001405 (central binomial coefficients): binomial(3*n,floor(3*n/2)), n>=0.
2
1, 3, 20, 126, 924, 6435, 48620, 352716, 2704156, 20058300, 155117520, 1166803110, 9075135300, 68923264410, 538257874440, 4116715363800, 32247603683100, 247959266474052, 1946939425648112, 15033633249770520, 118264581564861424
OFFSET
0,2
COMMENTS
For the trisection of sequences see a comment and a reference under A187357.
FORMULA
a(n) = binomial(3*n,floor(3*n/2)), n>=0.
O.g.f.: G0(x^2) + 3*x*G2(x^2) with G0(x) and G2(x) the o.g.f.s of A187363 and A187365, respectively.
MATHEMATICA
Table[Binomial[3n, Floor[(3n)/2]], {n, 0, 20}] (* Harvey P. Dale, Dec 23 2012 *)
CROSSREFS
A187443 binomial(3*n+1,floor((3*n+1)/2)),
A187444 binomial(3*n+2,floor((3*n+2)/2))/2.
Sequence in context: A325890 A323563 A228750 * A167590 A228884 A138910
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Mar 10 2011
STATUS
approved