A013148 tanh(tanh(x)+arctan(x))=2*x-20/3!*x^3+872/5!*x^5-82848/7!*x^7...

2, -20, 872, -82848, 13615232, -3427600128, 1224824628224, -589372636243968, 367372633732907008, -287938978919399424000, 277156456747324043952128, -321405895510495023427223552

Offset

0,1

Links

Table of n, a(n) for n=0..11.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Tanh[Tanh[x]+ArcTan[x]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Mar 21 2025 *)

Crossrefs

Sequence in context: A356691 A163594 A193483 * A276892 A006547 A290883

Adjacent sequences: A013145 A013146 A013147 * A013149 A013150 A013151

Keyword

sign

Author

Patrick Demichel

Status

approved