|
| |
|
|
A012726
|
|
arctanh(arctanh(x)*tan(x))=2/2!*x^2+16/4!*x^4+560/6!*x^6+39296/8!*x^8...
|
|
0
|
|
|
|
0, 2, 16, 560, 39296, 4768768, 881315840, 230827284480, 81324940394496, 37097190468747264, 21272100905987080192, 14977571327515946909696, 12703902924309766749552640, 12776509288228175937154318336
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,2
|
|
|
LINKS
|
|
|
|
FORMULA
|
a(n) ~ (2*n-1)! / r^(2*n), where r = 0.772419882704426062944736631601064953563... is the root of the equation arctanh(r)*tan(r) = 1. - Vaclav Kotesovec, Feb 05 2015
|
|
|
MATHEMATICA
|
With[{nn=30}, Flatten[{0, Take[CoefficientList[Series[ArcTanh[ArcTanh[x]Tan[x]], {x, 0, nn}], x] Range[0, nn]!, {3, -1, 2}]}]] (* Harvey P. Dale, Aug 26 2014 *)
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Patrick Demichel (patrick.demichel(AT)hp.com)
|
|
|
EXTENSIONS
|
|
|
|
STATUS
|
approved
|
| |
|
|
