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 A306832 Expansion of e.g.f. (sec(x) + tan(x))*exp(x)*BesselI(0,2*x). 0
 1, 2, 6, 21, 78, 317, 1394, 6713, 35518, 207017, 1326886, 9314173, 71206344, 589413593, 5253411102, 50166344891, 510988365078, 5530178925273, 63371129667726, 766522745352829, 9759669811328648, 130477170753991277, 1827415614960825342, 26757484944450577839, 408824255195817028276 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Boustrophedon transform of central trinomial coefficients (A002426). LINKS MATHEMATICA nmax = 24; CoefficientList[Series[(Sec[x] + Tan[x]) Exp[x] BesselI[0, 2 x], {x, 0, nmax}], x] Range[0, nmax]! t[n_, 0] := 3^n Hypergeometric2F1[ 1/2, -n, 1, 4/3]; 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, A002426, A306822. Sequence in context: A287211 A150193 A052300 * A121941 A150194 A150195 Adjacent sequences:  A306829 A306830 A306831 * A306833 A306834 A306835 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Apr 16 2019 STATUS approved

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Last modified April 9 16:39 EDT 2020. Contains 333361 sequences. (Running on oeis4.)