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A009530 Expansion of sin(tanh(x)/cos(x)). 2
1, 0, 12, -336, -2096, -1043328, -29488704, -8894706432, -389860902656, -170568226222080, -6327905330549760, -6080018829202427904, 242897035394043301888, -323994054628796940582912 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

Among solutions to a[x]=2x are primes, twice primes [A001747] and also further numbers.

MATHEMATICA

Sin[ Tanh[ x ]/Cos[ x ] ] (* Odd Part *)

CROSSREFS

Sequence in context: A153468 A110101 A185247 * A159363 A009680 A027015

Adjacent sequences:  A009527 A009528 A009529 * A009531 A009532 A009533

KEYWORD

sign

AUTHOR

R. H. Hardin (rhhardin(AT)att.net)

EXTENSIONS

Extended with signs Mar 15 1997 by Olivier Gerard.

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Last modified February 16 14:37 EST 2012. Contains 205930 sequences.