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A012256 exp(tanh(arctan(x)))=1+x+1/2!*x^2-3/3!*x^3-15/4!*x^4+41/5!*x^5... 0
1, 1, 1, -3, -15, 41, 561, -1019, -38623, 12305, 4206881, 7478221, -661302639, -3005647943, 140958927825, 1143787246421, -38921417469119, -494108406644959, 13433349471318337, 250135591701350045 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..19.

CROSSREFS

Sequence in context: A249835 A295938 A096742 * A012222 A069267 A059270

Adjacent sequences:  A012253 A012254 A012255 * A012257 A012258 A012259

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified October 14 17:43 EDT 2019. Contains 328022 sequences. (Running on oeis4.)