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A009530 Expansion of sin(tanh(x)/cos(x)). +0
3
1, 0, 12, -336, -2096, -1043328, -29488704, -8894706432, -389860902656, -170568226222080, -6327905330549760, -6080018829202427904, 242897035394043301888, -323994054628796940582912 (list; graph; listen)
OFFSET

0,3

COMMENT

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

MATHEMATICA

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

CROSSREFS

Adjacent sequences: A009527 A009528 A009529 this_sequence A009531 A009532 A009533

Sequence in context: A083431 A080141 A110101 this_sequence A009680 A027015 A024297

KEYWORD

sign

AUTHOR

R. H. Hardin (rhh(AT)cadence.com)

EXTENSIONS

Extended with signs Mar 15 1997 by Olivier Gerard.

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Last modified October 10 20:39 EDT 2008. Contains 144831 sequences.


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