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A009806 Expansion of tanh(tan(log(1+x))). 0
0, 1, -1, 2, -6, 16, 0, -792, 13776, -200552, 2855880, -41436352, 620388912, -9606956592, 153409074000, -2508503487232, 41503122145920, -680444083117184, 10600133081473152, -140189781816392448, 819083424632851200 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..20.

MATHEMATICA

Tanh[ Tan[ Log[ 1+x ] ] ]

CROSSREFS

Sequence in context: A009711 A009586 A009487 * A151708 A356370 A355096

Adjacent sequences: A009803 A009804 A009805 * A009807 A009808 A009809

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved

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Last modified January 27 12:14 EST 2023. Contains 359840 sequences. (Running on oeis4.)