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 A307593 Expansion of e.g.f. (sec(x) + tan(x))*exp(x)/(1 - x). 1
 1, 3, 10, 39, 180, 977, 6156, 44401, 361872, 3295025, 33193284, 366828033, 4414938000, 57501795977, 805984165252, 12098920460089, 193676009792768, 3293501718960033, 59294599560573508, 1126737323074730161, 22536528123718353104, 473290909667471110361 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Boustrophedon transform of A000522. LINKS MATHEMATICA nmax = 21; CoefficientList[Series[(Sec[x] + Tan[x]) Exp[x]/(1 - x), {x, 0, nmax}], x] Range[0, nmax]! t[n_, 0] := If[n < 1, 1, Floor[Exp[1] n!]]; t[n_, k_] := t[n, k] = t[n, k - 1] + t[n - 1, n - k]; a[n_] := t[n, n]; Array[a, 22, 0] CROSSREFS Cf. A000111, A000522, A230960, A307594. Sequence in context: A305560 A074728 A087860 * A221973 A303004 A054912 Adjacent sequences:  A307590 A307591 A307592 * A307594 A307595 A307596 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Apr 17 2019 STATUS approved

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Last modified August 18 20:02 EDT 2019. Contains 326109 sequences. (Running on oeis4.)