The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A009698

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A009698

Expansion of tan(tan(x))*sin(x).
(history; published version)

#12 by Vaclav Kotesovec at Fri Jan 23 14:35:50 EST 2015

STATUS

editing

approved

#11 by Vaclav Kotesovec at Fri Jan 23 14:35:45 EST 2015

FORMULA

a(n) ~ (2*n)! * 8 * Pi / ((4+Pi^2)^(3/2) * arctan(Pi/2)^(2*n+1)). - Vaclav Kotesovec, Jan 23 2015

#10 by Vaclav Kotesovec at Fri Jan 23 14:34:29 EST 2015

MATHEMATICA

nn = 20; Table[(CoefficientList[Series[Sin[x]*Tan[Tan[x]], {x, 0, 2*nn}], x] * Range[0, 2*nn]!)[[n]], {n, 1, 2*nn+1, 2}] (* Vaclav Kotesovec, Jan 23 2015 *)

STATUS

approved

editing

#9 by N. J. A. Sloane at Mon Jan 27 09:13:00 EST 2014

EXTENSIONS

Extended and signs tested Mar 15 1997 by _Olivier GerardGérard_.

Discussion

Mon Jan 27

09:13

OEIS Server: https://oeis.org/edit/global/2111

#8 by Russ Cox at Sat Mar 31 12:34:56 EDT 2012

AUTHOR

_R. H. Hardin (rhhardin(AT)att.net)_

Discussion

Sat Mar 31

12:34

OEIS Server: https://oeis.org/edit/global/875

#7 by N. J. A. Sloane at Fri Jan 09 03:00:00 EST 2009

KEYWORD

nonn,new

nonn

AUTHOR

R. H. Hardin (rhhrhhardin(AT)cadenceatt.comnet)

#6 by N. J. A. Sloane at Sat Jun 12 03:00:00 EDT 2004

NAME

Expansion of tan(tan(x)).*sin(x).

KEYWORD

nonn,new

nonn

#5 by N. J. A. Sloane at Fri May 16 03:00:00 EDT 2003

KEYWORD

nonn,new

nonn

AUTHOR

R. H. Hardin (rhh@research.att(AT)cadence.com)

EXTENSIONS

Extended and signs tested 03/97 Mar 15 1997 by Olivier Gerard.

#4 by N. J. A. Sloane at Sat Dec 11 03:00:00 EST 1999

MATHEMATICA

Tan[ Tan[ x ] ]*Sin[ x ] (* Even Part *)

KEYWORD

nonn,new

nonn

#3 by N. J. A. Sloane at Sun Jun 14 03:00:00 EDT 1998

NAME

Expansion of tan(tan($x$)).sin($x$).

DATA

1, 6, 179, 9676, 854597, 111361298, 20061390071, 4771665341848, 1447947783210249, 545795035419716382, 250167844738073041595, 1370139897568444961682920, 2, 12, 358, 19352, 1709194, 222722596, 40122780142, 9543330683696, 2895895566420498, 1091590070839432764, 500335689476146083190, 274027979513688992336584, 176734166480671985581245594

REFERENCES

MATHEMATICA

Tan[Tan[x]]*Sin[x] (* Even Part *)

KEYWORD

,new

nonn

EXTENSIONS

Extended and signs tested 03/97 by Olivier Gerard.