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A012663
Expansion of e.g.f.: sech(tanh(x)*exp(x))=1-1/2!*x^2-6/3!*x^3-11/4!*x^4+100/5!*x^5...
0
1, 0, -1, -6, -11, 100, 1043, 2702, -47287, -697656, -2382009, 65150690, 1227815037, 4876299948, -197964434917, -4452683466122, -19212329422319, 1119650941512592, 28926172679801103, 128264089711760074
OFFSET
0,4
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Sech[Tanh[x]Exp[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jun 23 2013 *)
CROSSREFS
Sequence in context: A188599 A217934 A012419 * A180929 A212592 A351991
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Definition clarified by Harvey P. Dale, Jun 23 2013
STATUS
approved