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A013144 arctan(tanh(x)+arctan(x))=2*x-20/3!*x^3+1128/5!*x^5-158112/7!*x^7... 0
2, -20, 1128, -158112, 41334912, -17364051712, 10697958401024, -9087507664709632, 10179531541621604352, -14538540850131730563072, 25785525466844174964228096, -55601885971190702384095952896 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..11.

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[ArcTan[Tanh[x]+ArcTan[x]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Ray Chandler, Nov 29 2016 *)

CROSSREFS

Sequence in context: A015192 A012790 A273194 * A239642 A112359 A308231

Adjacent sequences:  A013141 A013142 A013143 * A013145 A013146 A013147

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified May 16 16:43 EDT 2022. Contains 353707 sequences. (Running on oeis4.)