login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A009374 Expansion of log(1+tan(x))/exp(x). 5
0, 1, -3, 10, -40, 205, -1287, 9714, -85384, 859889, -9751651, 123102098, -1711387808, 25985945453, -427828028695, 7591346835562, -144408464041712, 2931676572255297, -63262735545686819, 1445955290624608506 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..19.

FORMULA

a(n) ~ (n-1)! * (-1)^(n+1) * exp(Pi/4) * (4/Pi)^n. - Vaclav Kotesovec, Jan 23 2015

MATHEMATICA

Log[ 1+Tan[ x ] ]/Exp[ x ]

CoefficientList[Series[Log[1 + Tan[x]]/E^x, {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 23 2015 *)

CROSSREFS

Sequence in context: A030868 A030891 A030911 * A297213 A216386 A256157

Adjacent sequences:  A009371 A009372 A009373 * A009375 A009376 A009377

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 1 22:12 EST 2021. Contains 349435 sequences. (Running on oeis4.)