login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A009310 Expansion of log(1+log(1+tan(x))). 0
0, 1, -2, 9, -51, 384, -3506, 38126, -479770, 6872392, -110410296, 1967181840, -38502498592, 821352161200, -18969587297792, 471608373782864, -12558441874756176, 356636706706414848, -10759204665600245888 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..18.

FORMULA

a(n) ~ (n-1)! * (-1)^(n+1) / (arctan(1-exp(-1))^n). - Vaclav Kotesovec, Jan 22 2015

MATHEMATICA

Log[ 1+Log[ 1+Tan[ x ] ] ]

CoefficientList[Series[Log[1 + Log[1 + Tan[x]]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 22 2015 *)

CROSSREFS

Sequence in context: A079836 A026945 A246464 * A091319 A193465 A003584

Adjacent sequences:  A009307 A009308 A009309 * A009311 A009312 A009313

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 23 11:08 EST 2018. Contains 299538 sequences. (Running on oeis4.)