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A012809 tanh(sec(x)*arctan(x))=x-1/3!*x^3+25/5!*x^5-1209/7!*x^7+68945/9!*x^9... 0
1, -1, 25, -1209, 68945, -7692881, 1181481769, -242740782153, 66317255314721, -22739603323053601, 9634203397240829625, -4937246969845634306905, 3007627322996781467655025, -2149125294837930108279760753, 1779707247211878394671148764873 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
MATHEMATICA
With[{nn=40}, Take[CoefficientList[Series[Tanh[Sec[x]ArcTan[x]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Dec 29 2013 *)
CROSSREFS
Sequence in context: A112102 A012799 A120694 * A014769 A012851 A181719
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
More terms from Harvey P. Dale, Dec 29 2013
STATUS
approved

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Last modified July 12 07:24 EDT 2024. Contains 374237 sequences. (Running on oeis4.)