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%I #8 Jun 11 2015 12:25:26
%S 1,5,35,231,1716,12155,92378,676039,5200300,38779380,300540195,
%T 2268783825,17672631900,134564468610,1052049481860,8061900920775,
%U 63205303218876,486734856412028,3824345300380220,29566145391215356,232714176627630544,1804857108504066435
%N A trisection of A001405 (central binomial coefficients): binomial(3n+2,floor((3n+2)/2))/2, n>=0.
%C For the trisection of sequences see a comment and a reference under A187357.
%F a(n) = binomial(3*n+2,floor((3*n+2)/2))/2, n>=0.
%F 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.
%o (PARI) vector(30, n, n--; binomial(3*n+2,(3*n+2)\2)/2) \\ _Michel Marcus_, Jun 11 2015
%Y Cf. A187442: binomial(3*n,floor(3*n/2)), A187443: binomial(3*n+1,floor((3*n+1)/2)).
%K nonn,easy
%O 0,2
%A _Wolfdieter Lang_, Mar 10 2011