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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A003702 Expansion of tan(x)/cosh(x). (Formerly M5110) 5
 1, -1, 21, -141, 10441, -183481, 29429661, -987318021, 276117553681, -15085947275761, 6514632269358501, -526614587249608701, 324871912636292700121, -36433570919762397948841, 30417659816002454665514541 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 REFERENCES N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Vaclav Kotesovec, Table of n, a(n) for n = 0..240 (first 50 terms from T. D. Noe) FORMULA a(n) ~ (2*exp(Pi/2) + (exp(Pi) - 1)*(-1)^n) * (2*n+1)! * 2^(2*n+3) / ((1+exp(Pi)) * Pi^(2*n+2)). - Vaclav Kotesovec, Feb 16 2015 MATHEMATICA Tan[ x ]/Cosh[ x ] (* Odd Part *) nn = 20; Table[(CoefficientList[Series[Sech[x]*Tan[x], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Feb 16 2015 *) CROSSREFS Sequence in context: A337899 A200987 A107731 * A221785 A301866 A101645 Adjacent sequences: A003699 A003700 A003701 * A003703 A003704 A003705 KEYWORD sign AUTHOR R. H. Hardin, Simon Plouffe 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 November 28 13:32 EST 2023. Contains 367419 sequences. (Running on oeis4.)