The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A009131 Expansion of e.g.f. cosh(log(1+x))/cosh(x). 1
 1, 0, 0, -3, 11, -30, 194, -1785, 13957, -113148, 1143284, -13131855, 156950639, -2005222362, 28119703702, -424785970245, 6792043718345, -115135087505400, 2072993596779944, -39432571052652315, 788564865102950035 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS G. C. Greubel, Table of n, a(n) for n = 0..250 FORMULA a(n) ~ n! * (-1)^n / (exp(1) + exp(-1)). - Vaclav Kotesovec, Jan 22 2015 MATHEMATICA CoefficientList[Series[((1 + (1 + x)^2)*Sech[x])/(2*(1 + x)), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 22 2015 *) PROG (PARI) x='x+O('x^30); Vec(serlaplace(cosh(log(1+x))/cosh(x))) \\ G. C. Greubel, Jul 28 2018 (Magma) m:=30; R:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(Cosh(Log(1+x))/Cosh(x))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, Jul 28 2018 CROSSREFS Sequence in context: A330148 A085376 A196233 * A003554 A003523 A018781 Adjacent sequences: A009128 A009129 A009130 * A009132 A009133 A009134 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 25 12:59 EST 2024. Contains 370328 sequences. (Running on oeis4.)