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 A012416 arctanh(arctan(x)*exp(x))=x+2/2!*x^2+3/3!*x^3+20/4!*x^4+173/5!*x^5... 0
 0, 1, 2, 3, 20, 173, 1190, 11039, 140968, 1855481, 26494858, 441706331, 8105309500, 159190672613, 3403623626286, 78823813121975, 1949180731782480, 51354602068725361, 1439864769232356882 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS FORMULA a(n) ~ (n-1)! / (2 * r^n), where r = 0.606555409757505028513842694060977136299... is the root of the equation arctan(r)*exp(r) = 1. - Vaclav Kotesovec, Feb 05 2015 MATHEMATICA With[{nn=25}, CoefficientList[Series[ArcTanh[ArcTan[x]Exp[x]], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Oct 21 2011 *) CROSSREFS Sequence in context: A009721 A013340 A218873 * A261317 A177946 A006246 Adjacent sequences:  A012413 A012414 A012415 * A012417 A012418 A012419 KEYWORD nonn AUTHOR Patrick Demichel (patrick.demichel(AT)hp.com) EXTENSIONS Prepended missing a(0)=0 from Vaclav Kotesovec, Feb 05 2015 STATUS approved

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