The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A009196 Expansion of e.g.f. exp(log(1+x)/cos(x)). 1
 1, 1, 0, 3, 6, 15, 195, 126, 6860, 10581, 275955, 1581734, 11684442, 223836379, 423165561, 32439219242, 10301267912, 4976257880345, 4959730228167, 803695677341350, 3521551886934550, 131556027669677615, 1743242423131143869, 19663074849601180770 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS Note that a(27) is negative. - Vaclav Kotesovec, Jan 24 2015 LINKS Andrew Howroyd, Table of n, a(n) for n = 0..200 FORMULA a(n) ~ n! * (-1)^n / (GAMMA(-1/cos(1)) * n^(1+1/cos(1))) * (1 - sin(1)*log(n)/((cos(1))^2*n)*(1+1/cos(1))). - Vaclav Kotesovec, Jan 24 2015 MATHEMATICA Exp[ Log[ 1+x ]/Cos[ x ] ] CoefficientList[Series[(1 + x)^Sec[x], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 24 2015 *) PROG (PARI) seq(n)={my(x='x+O('x^n)); Vec(serlaplace(exp(log(1+x)/cos(x))))} \\ Andrew Howroyd, Feb 25 2018 CROSSREFS Sequence in context: A013271 A013272 A013278 * A329124 A116613 A291803 Adjacent sequences:  A009193 A009194 A009195 * A009197 A009198 A009199 KEYWORD sign,easy AUTHOR EXTENSIONS Extended with signs by Olivier Gérard, Mar 15 1997 a(22)-a(23) from Andrew Howroyd, Feb 25 2018 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.

Last modified January 16 17:26 EST 2021. Contains 340206 sequences. (Running on oeis4.)