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 A306836 Expansion of e.g.f. (sec(x) + tan(x))*exp(x)*BesselI(1,2*x)/x. 0
 1, 2, 5, 15, 50, 187, 779, 3626, 18830, 108737, 694156, 4865168, 37175028, 307674135, 2742199399, 26185972811, 266727515558, 2886665421697, 33078737906112, 400112950565602, 5094396150412628, 68107059089489867, 953882607872927724, 13966992152276252633, 213399920723596392052 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Boustrophedon transform of Motzkin numbers (A001006). LINKS MATHEMATICA nmax = 24; CoefficientList[Series[(Sec[x] + Tan[x]) Exp[x] BesselI[1, 2 x]/x, {x, 0, nmax}], x] Range[0, nmax]! t[n_, 0] := Hypergeometric2F1[(1 - n)/2, -n/2, 2, 4]; t[n_, k_] := t[n, k] = t[n, k - 1] + t[n - 1, n - k]; a[n_] := t[n, n]; Array[a, 25, 0] CROSSREFS Cf. A000111, A000753, A001006. Sequence in context: A107590 A245311 A148367 * A192634 A304386 A140639 Adjacent sequences:  A306833 A306834 A306835 * A306837 A306838 A306839 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Apr 16 2019 STATUS approved

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Last modified April 5 09:06 EDT 2020. Contains 333238 sequences. (Running on oeis4.)