A013100 cosh(arcsinh(x)+tan(x))=1+4/2!*x^2+24/4!*x^4+534/6!*x^6+16520/8!*x^8...

1, 4, 24, 534, 16520, 1017914, 66612612, 8612481206, 839464647792, 223263066398386, 20349154329810172, 15355587487339427086, -408311328299061735320, 2681720930486026740373066, -832148640269649203971185996, 1101363338244005265784426750566

Offset

0,2

Links

Table of n, a(n) for n=0..15.

Formula

a(n) ~ (-1)^(n+1) * 2^(2*n) * n^(2*n-1) * cos(tanh(1)) / exp(2*n). - Vaclav Kotesovec, Nov 01 2013

Mathematica

With[{nn=40}, Take[CoefficientList[Series[Cosh[ArcSinh[x]+Tan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Feb 23 2013 *)

Crossrefs

Sequence in context: A139096 A111425 A374068 * A013061 A071302 A211215

Adjacent sequences: A013097 A013098 A013099 * A013101 A013102 A013103

Keyword

sign

Author

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

Extensions

Checked by N. J. A. Sloane, Dec 17 2011

More terms from Harvey P. Dale, Feb 23 2013

Status

approved