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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
OFFSET
0,2
LINKS
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
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