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A012735 cosh(arctanh(x)*arctan(x)) = 1+12/4!*x^4+13328/8!*x^8+123701952/12!*x^12... 1
1, 12, 13328, 123701952, 4532782825728, 459909185638812672, 104929881035116227072000, 46932023772320615610531102720, 37335044041745321283133064572108800, 49122678379677747841112058639072413614080, 101040224553048123974208287067140687061807267840 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..50

MATHEMATICA

With[{nn=40}, Take[CoefficientList[Series[Cosh[ArcTanh[x]ArcTan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 4}]] (* Harvey P. Dale, May 31 2014 *)

CROSSREFS

Sequence in context: A159413 A317958 A012608 * A012674 A301533 A013514

Adjacent sequences:  A012732 A012733 A012734 * A012736 A012737 A012738

KEYWORD

nonn

AUTHOR

Patrick Demichel (patrick.demichel(AT)hp.com)

EXTENSIONS

More terms from and definition clarified by Harvey P. Dale, May 31 2014

STATUS

approved

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Last modified September 28 09:11 EDT 2022. Contains 357068 sequences. (Running on oeis4.)