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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A013559 Numerator of [x^n] in the Taylor expansion of exp(cosech(x)-coth(x)). 1
1, -1, 1, 1, -7, 1, 97, -55, -2063, 143, 17803, -968167, -250781, 7000033, -166831871, -571772647, 43685848289, 843598411471, -447550424579, -1263845119891, 84677077231169, 740683182137153, -11657476758734011, -474904166544135457, 28924058075775365981, -2379183287545454197 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

The inner function is cosech(x)-coth(x) = -x/2 +x^3/24 -x^5/240 +17*x^7/40320 -31*x^9/725760 +691*x^11/159667200 -... with e.g.f numerators cosech(x)-coth(x) = sum b(n)x^n/(n+1)! apparently in A001469.

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..400

EXAMPLE

1-x/2 +x^2/8 +x^3/48 -7*x^4/384 +x^5/1280 +97*x^6/46080 -...

MAPLE

S:= series(exp(csch(x)-coth(x)), x, 51):

seq(numer(coeff(S, x, j)), j=0..50); # Robert Israel, Nov 14 2016

MATHEMATICA

Numerator[Take[CoefficientList[Series[Exp[Csch[x] - Coth[x]], {x, 0, 40}], x], {1, -1, 1}]] (* G. C. Greubel, Nov 13 2016 *)

CROSSREFS

Cf. A013521, A096664 (bisections?)

Sequence in context: A027447 A027517 A092082 * A051186 A012034 A138324

Adjacent sequences:  A013556 A013557 A013558 * A013560 A013561 A013562

KEYWORD

sign

AUTHOR

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

EXTENSIONS

Name edited by R. J. Mathar, Dec 22 2011

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 March 28 21:25 EDT 2017. Contains 284246 sequences.