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A257633
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a(n) = binomial(4*n + 2,n).
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6
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1, 6, 45, 364, 3060, 26334, 230230, 2035800, 18156204, 163011640, 1471442973, 13340783196, 121399651100, 1108176102180, 10142940735900, 93052749919920, 855420636763836, 7877932561061640, 72667580816130436, 671262558647881200, 6208770443303347920
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OFFSET
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0,2
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LINKS
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FORMULA
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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).
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MAPLE
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seq(binomial(4*n + 2, n), n = 0..20);
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PROG
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(PARI) vector(30, n, n--; binomial(4*n+2, n)) \\ Altug Alkan, Nov 05 2015
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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