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A012180 tanh(tan(arctanh(x)))=x+2/3!*x^3+16/5!*x^5+48/7!*x^7-29696/9!*x^9... 0
1, 2, 16, 48, -29696, -6049792, -1262426112, -308569372672, -89297625350144, -30123113337716736, -11520007513318621184, -4775431672418431664128, -1952929261585732032528384, -545214673336986589066166272 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[Tanh[Tan[ArcTanh[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Sep 06 2023 *)
CROSSREFS
Sequence in context: A223219 A063721 A232209 * A058376 A295906 A120948
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved

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Last modified May 19 03:29 EDT 2024. Contains 372666 sequences. (Running on oeis4.)