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

 

Logo

Many excellent designs for a new banner were submitted. We will use the best of them in rotation.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A009570 Expansion of sinh(ln(1+tanh(x))). 1
0, 1, -1, 1, -4, 16, -16, -104, -64, 4096, -256, -176384, -1024, 11186176, -4096, -951870464, -16384, 104932704256, -65536, -14544442425344, -262144, 2475749027086336, -1048576, -507711943251329024, -4194304, 123460740095112380416, -16777216 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..26.

FORMULA

E.g.f.: (1/Q(0)-Q(0))/2, where Q(k) = 1 - x/( 2*k+1 + x/Q(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Dec 20 2013

MATHEMATICA

Sinh[ Log[ 1+Tanh[ x ] ] ]

CROSSREFS

Cf. A009126.

Sequence in context: A229105 A223585 A202680 * A232839 A140299 A119007

Adjacent sequences:  A009567 A009568 A009569 * A009571 A009572 A009573

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 | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified April 18 05:20 EDT 2014. Contains 240688 sequences.