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 A307376 a(n) = 1/n! * Sum_{k=0..n} (2*n+k)!/((n-k)!*k!*2^k). 1
 1, 5, 81, 2330, 97405, 5360607, 366432990, 29948982492, 2849278444155, 309333396512855, 37741150862494651, 5112458462852223210, 761358344010536141506, 123636426598733578925150, 21742842987398075489784900, 4116720379411455407932693320, 834934865669512891440715729125 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Seiichi Manyama, Table of n, a(n) for n = 0..313 FORMULA a(n) = (-1)^n * A144505(2*n+1, n). a(n) ~ 3^(3*n + 1/2) * n^(n - 1/2) / (sqrt(Pi) * 2^(n + 1/2) * exp(n - 2/3)). - Vaclav Kotesovec, Apr 06 2019 MATHEMATICA Table[Sum[(2*n + k)!/((n - k)!*k!*2^k)/n!, {k, 0, n}], {n, 0, 20}] (* Vaclav Kotesovec, Apr 06 2019 *) PROG (PARI) {a(n) = sum(k=0, n, (2*n+k)!/((n-k)!*k!*2^k))/n!} CROSSREFS Cf. A144505. Sequence in context: A135918 A115032 A278883 * A009733 A009756 A336807 Adjacent sequences: A307373 A307374 A307375 * A307377 A307378 A307379 KEYWORD nonn AUTHOR Seiichi Manyama, Apr 06 2019 STATUS approved

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Last modified February 2 02:24 EST 2023. Contains 359997 sequences. (Running on oeis4.)