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A012508 sech(cos(x)*arctan(x))=1-1/2!*x^2+25/4!*x^4-1105/6!*x^6+91313/8!*x^8... 0
1, -1, 25, -1105, 91313, -12232385, 2400320393, -649247356433, 231544408317537, -105271075840787713, 59429582363323624185, -40787189186519841731153, 33444147237661076070865681 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..12.

CROSSREFS

Sequence in context: A246923 A066852 A123204 * A112102 A012799 A120694

Adjacent sequences:  A012505 A012506 A012507 * A012509 A012510 A012511

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified February 18 03:28 EST 2018. Contains 299298 sequences. (Running on oeis4.)