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A013151 sech(tanh(x)+arctan(x))=1-4/2!*x^2+112/4!*x^4-7744/6!*x^6... 0
1, -4, 112, -7744, 995840, -205558144, 62203595776, -25948859891712, 14273513699311616, -10010170584339742720, 8717845696617764192256, -9230668213290446763196416, 11677592409577212192402440192 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

CROSSREFS

Sequence in context: A158450 A063406 A221625 * A006718 A185320 A293158

Adjacent sequences:  A013148 A013149 A013150 * A013152 A013153 A013154

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified December 8 20:37 EST 2021. Contains 349596 sequences. (Running on oeis4.)