|
|
A012757
|
|
tan(arctanh(x)^2) = 2/2!*x^2 + 16/4!*x^4 + 608/6!*x^6 + 43776/8!*x^8 + ...
|
|
0
|
|
|
0, 2, 16, 608, 43776, 5248512, 937297920, 232869949440, 76704079872000, 32321764442112000, 16950418888812134400, 10823130351189900656640, 8265103101463254238494720, 7437225349735123409814159360
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
a(n) ~ 2^(3/2) * (2*n)! / (sqrt(Pi) * sinh(sqrt(2*Pi)) * (tanh(sqrt(Pi/2)))^(2*n)). - Vaclav Kotesovec, Feb 06 2015
|
|
MATHEMATICA
|
With[{nn=30}, Take[CoefficientList[Series[Tan[ArcTanh[x]^2], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Mar 31 2013 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Patrick Demichel (patrick.demichel(AT)hp.com)
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|