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%I #9 Nov 05 2015 04:03:57
%S 1,6,45,364,3060,26334,230230,2035800,18156204,163011640,1471442973,
%T 13340783196,121399651100,1108176102180,10142940735900,93052749919920,
%U 855420636763836,7877932561061640,72667580816130436,671262558647881200,6208770443303347920
%N a(n) = binomial(4*n + 2,n).
%F The o.g.f. equals f(x)*g(x)^2, where f(x) is the o.g.f. for A005810 and g(x) is the o.g.f. for A002293. More generally, f(x)*g(x)^k is the o.g.f. for the sequence binomial(4*n + k,n). Cf. A262977 (k = -1), A005810 (k = 0), A052203 (k = 1), A224274 (k = 3) and A004331 (k = 4).
%p #A257633
%p seq(binomial(4*n + 2,n), n = 0..20);
%o (PARI) vector(30, n, n--; binomial(4*n+2, n)) \\ _Altug Alkan_, Nov 05 2015
%Y Cf. A002293, A004331, A005810, A052203, A224274, A262977.
%K nonn,easy
%O 0,2
%A _Peter Bala_, Nov 04 2015
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