A012450 arcsinh(arctan(x)*tan(x))=2/2!*x^2+40/6!*x^6-2688/8!*x^8+210208/10!*x^10...

2, 0, 40, -2688, 210208, -13038080, 2241915520, -589026013184, 146361182839296, -42690102749216768, 18963982821764573184, -10109322351828827471872, 5702647873782168851521536

Offset

1,1

Links

Table of n, a(n) for n=1..13.

Formula

a(n) = (2n)! [ x^(2n) ] arcsinh(arctan(x)*tan(x)).

Crossrefs

Sequence in context: A230888 A185281 A012445 * A303491 A303396 A319113

Adjacent sequences: A012447 A012448 A012449 * A012451 A012452 A012453

Keyword

sign

Author

Patrick Demichel

Status

approved