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A296544
Expansion of e.g.f. sech(exp(x)-1).
2
1, 0, -1, -3, -2, 35, 233, 406, -6463, -72951, -234204, 3454165, 59129541, 299098488, -3983040037, -98320221991, -717243756890, 8306677424447, 290745526287213, 2888789037885782, -27716446593438731, -1389236305462658939, -18071746125863480076, 133495439954224143065, 10011730596035533451801
OFFSET
0,4
FORMULA
E.g.f. 1/cosh(exp(x)-1).
EXAMPLE
sech(exp(x)-1) = 1 - x^2/2! - 3*x^3/3! - 2*x^4/4! + 35*x^5/5! + 233*x^6/6! + ...
MAPLE
a:=series(sech(exp(x)-1), x=0, 25): seq(n!*coeff(a, x, n), n=0..24); # Paolo P. Lava, Mar 27 2019
MATHEMATICA
nmax = 24; CoefficientList[Series[Sech[Exp[x] - 1], {x, 0, nmax}], x] Range[0, nmax]!
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Dec 15 2017
STATUS
approved