This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A187444 #8 Jun 11 2015 12:25:26 %S A187444 1,5,35,231,1716,12155,92378,676039,5200300,38779380,300540195, %T A187444 2268783825,17672631900,134564468610,1052049481860,8061900920775, %U A187444 63205303218876,486734856412028,3824345300380220,29566145391215356,232714176627630544,1804857108504066435 %N A187444 A trisection of A001405 (central binomial coefficients): binomial(3n+2,floor((3n+2)/2))/2, n>=0. %C A187444 For the trisection of sequences see a comment and a reference under A187357. %F A187444 a(n) = binomial(3*n+2,floor((3*n+2)/2))/2, n>=0. %F A187444 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 A187444 (PARI) vector(30, n, n--; binomial(3*n+2,(3*n+2)\2)/2) \\ _Michel Marcus_, Jun 11 2015 %Y A187444 Cf. A187442: binomial(3*n,floor(3*n/2)), A187443: binomial(3*n+1,floor((3*n+1)/2)). %K A187444 nonn,easy %O A187444 0,2 %A A187444 _Wolfdieter Lang_, Mar 10 2011