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!)
A012003 E.g.f. cos(log(cos(x))), even powers only. 2
1, 0, -3, -30, -483, -12660, -492063, -26407290, -1854592743, -162954226920, -17150991170523, -2051454240374550, -254425037609483403, -24186909676571913180, 3098088521295623020617 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..14.

FORMULA

For n>1, a(n) appears to be divisible by 3, and the highest exponent of 2 in a(2m+1) seems to be A001511(m). - Ralf Stephan, Aug 14 2013

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Cos[Log[Cos[x]]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Aug 29 2011 *)

CROSSREFS

Sequence in context: A218304 A242005 A276356 * A164945 A201466 A064352

Adjacent sequences:  A012000 A012001 A012002 * A012004 A012005 A012006

KEYWORD

sign

AUTHOR

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

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 6 00:51 EST 2021. Contains 349558 sequences. (Running on oeis4.)