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A009823 Expansion of tanh(tanh(x)*tan(x))/2. 1
1, -64, 6016, 182844416, -1001405579264, -33574129505665024, 1883390165749948481536, 20340448295605095121289216, -36112647755760335076622057078784 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
MATHEMATICA
With[{nn=40}, Take[CoefficientList[Series[Tanh[Tanh[x]*Tan[x]]/2, {x, 0, nn}], x] Range[0, nn-2]!, {3, -1, 4}]] (* Harvey P. Dale, Mar 31 2019 *)
CROSSREFS
Cf. A012673.
Sequence in context: A316821 A317571 A240346 * A222100 A223265 A266631
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs Mar 1997
Previous Mathematica program replaced by Harvey P. Dale, Mar 31 2019
STATUS
approved

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Last modified July 22 13:14 EDT 2024. Contains 374499 sequences. (Running on oeis4.)