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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A012821 Expansion of e.g.f. exp(sec(x)*arcsinh(x)). 2
1, 1, 1, 3, 9, 45, 225, 1071, 6993, 56697, 467745, 3279419, 29529753, 376156261, 4297350785, 35274762407, 378759492257, 8003761282417, 122599030798017, 853554115621363, 8002975063348265, 450081179390735645 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

The first negative number is a(24) = -686072407102337430543.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..200

EXAMPLE

exp(sec(x)*arcsinh(x)) = 1 + x + 1/2!*x^2 + 3/3!*x^3 + 9/4!*x^4 + 45/5!*x^5 + ...

PROG

(PARI) seq(n)={my(x='x+O('x^n)); Vec(serlaplace(exp(asinh(x)/cos(x))))} \\ Andrew Howroyd, Feb 25 2018

CROSSREFS

Sequence in context: A192891 A068100 A262129 * A229813 A262130 A262131

Adjacent sequences:  A012818 A012819 A012820 * A012822 A012823 A012824

KEYWORD

sign

AUTHOR

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

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 November 18 07:53 EST 2018. Contains 317279 sequences. (Running on oeis4.)