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A012749 sech(arctanh(x)*cos(x))=1-1/2!*x^2+9/4!*x^4-225/6!*x^6+6993/8!*x^8... 0
1, -1, 9, -225, 6993, -592545, 38019993, -7568120833, 704958936737, -307874830583745, 28902473366214185, -31727751790145150113, 1072204316646061940721, -7192967681050724533661025 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..13.

CROSSREFS

Sequence in context: A063386 A063392 A012831 * A188662 A079727 A251579

Adjacent sequences:  A012746 A012747 A012748 * A012750 A012751 A012752

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified September 25 12:12 EDT 2022. Contains 356984 sequences. (Running on oeis4.)