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A009711
Expansion of e.g.f.: tan(tanh(log(1+x))).
0
0, 1, -1, 2, -6, 16, 0, -568, 7504, -78248, 739080, -6314848, 44072688, -125928464, -3754236304, 114500663552, -2264653307520, 37495468333696, -536284797406848, 6159440282136320, -34551694794080000, -931439976890484224
OFFSET
0,4
MATHEMATICA
With[{nn=30}, CoefficientList[Series[Tan[Tanh[Log[1+x]]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Aug 30 2020 *)
CROSSREFS
Sequence in context: A181993 A123475 A193341 * A009586 A009487 A009806
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
Definition clarified and previous Mathematica program replaced by Harvey P. Dale, Aug 30 2020
STATUS
approved