A306857 Expansion of e.g.f. (sec(x) + tan(x))/(2 - exp(x)).

1, 2, 6, 27, 158, 1147, 9956, 100667, 1162478, 15097487, 217833456, 3457099107, 59851694498, 1122530734327, 22672663147556, 490646937984347, 11325671204407718, 277771419131565167, 7213311163322015256, 197725569735723642387, 5705154145153596656138, 172846751677879951716007

Offset

0,2

Comments

Boustrophedon transform of Fubini numbers (A000670).

Links

Table of n, a(n) for n=0..21.

Index entries for sequences related to boustrophedon transform

Mathematica

nmax = 21; CoefficientList[Series[(Sec[x] + Tan[x])/(2 - Exp[x]), {x, 0, nmax}], x] Range[0, nmax]!
t[n_, 0] := HurwitzLerchPhi[1/2, -n, 0]/2; 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, A000670, A000764.

Sequence in context: A338180 A307595 A058133 * A321584 A009308 A032186

Adjacent sequences: A306854 A306855 A306856 * A306858 A306859 A306860

Keyword

nonn

Author

Ilya Gutkovskiy, Apr 16 2019

Status

approved