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A013339 sech(exp(x)-sec(x))=1-1/2!*x^2+1/4!*x^4+20/5!*x^5+23/6!*x^6... 0
1, 0, -1, 0, 1, 20, 23, -140, -975, -1656, 74751, 365640, 1284369, -26269412, -120532297, 1518753340, 37230940193, 312855107472, -1646816770497, -37424409392880, -167334452580383, 9798194248744356 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

LINKS

Table of n, a(n) for n=0..21.

CROSSREFS

Sequence in context: A153717 A303303 A045563 * A199360 A199585 A093716

Adjacent sequences:  A013336 A013337 A013338 * A013340 A013341 A013342

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified August 3 14:40 EDT 2021. Contains 346438 sequences. (Running on oeis4.)