A013047 tan(sinh(x)+tan(x))=2*x+19/3!*x^3+769/5!*x^5+67345/7!*x^7...

2, 19, 769, 67345, 10170577, 2350029977, 770367837321, 339987628582481, 194352713896710433, 139694411950654484905, 123308135456808383622937, 131131181574217458549045281, 165356414397352918016200574961

Offset

0,1

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..200

Vaclav Kotesovec, Graph - abs(e.g.f.) in the complex plane

Formula

a(n) ~ 2 * (2*n+1)! / ((cosh(r) + 1/(cos(r))^2) * r^(2*n+2)), where r = 0.6897918664614192227814262662202471295055814443118279957952... is the root of the equation sinh(r) + tan(r) = Pi/2. - Vaclav Kotesovec, Feb 07 2015

Mathematica

nn = 20; Table[(CoefficientList[Series[Tan[Sinh[x] + Tan[x]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Feb 07 2015 *)

Crossrefs

Sequence in context: A118189 A062623 A155956 * A012951 A012980 A323280

Adjacent sequences: A013044 A013045 A013046 * A013048 A013049 A013050

Keyword

nonn

Author

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

Status

approved