The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A071968 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A071968

Denominators of coefficients of expansion of arctan(x)^2 = x^2-2/3*x^4+23/45*x^6-44/105*x^8+563/1575*x^10-3254/10395*x^12+ ...
(history; published version)

#8 by Bruno Berselli at Mon Nov 04 05:30:47 EST 2013

STATUS

proposed

approved

#7 by Jean-François Alcover at Mon Nov 04 04:52:42 EST 2013

STATUS

editing

proposed

#6 by Jean-François Alcover at Mon Nov 04 04:15:23 EST 2013

MATHEMATICA

a[n_] := (-1)^(n+1)*Sum[1/(n*(2*k-1)), {k, 1, n}] // Denominator; Table[a[n], {n, 0, 19}] (* Jean-François Alcover, Nov 04 2013 *)

STATUS

approved

editing

#5 by Joerg Arndt at Thu Aug 02 07:06:43 EDT 2012

COMMENTS

Denominators of coefficients of expansion of (ln((1+z)/(1-z))/2)^2=z^2+2/3z^4+23/45z^6+44/105z^

8+563/1575z^10+3254/10395z^12+88069/315315z^14+11384/45045z^16+

1593269/6891885z^18+15518938/72747675z^

20+...[From Leonid Bedratyuk, July 30, 2012]

KEYWORD

nonn,easy,frac,changed

STATUS

editing

approved

#4 by Leonid Bedratyuk at Sun Jul 29 18:19:27 EDT 2012

COMMENTS

Denominators of coefficients of expansion of (ln((1+z)/(1-z))/2)^2=z^2+2/3z^4+23/45z^6+44/105z^

8+563/1575z^10+3254/10395z^12+88069/315315z^14+11384/45045z^16+

1593269/6891885z^18+15518938/72747675z^

20+...[From Leonid Bedratyuk, July 30, 2012]

STATUS

approved

editing

Discussion

Mon Jul 30

14:16

Leonid Bedratyuk: I withdraw my editing

#3 by Russ Cox at Fri Mar 30 16:49:29 EDT 2012

AUTHOR

_N. J. A. Sloane (njas(AT)research.att.com), _, Jun 17 2002

Discussion

Fri Mar 30

16:49

OEIS Server: https://oeis.org/edit/global/110

#2 by N. J. A. Sloane at Fri Feb 27 03:00:00 EST 2009

KEYWORD

nonn,easy,frac,new

AUTHOR

N. J. A. Sloane (njas, (AT)research.att.com), Jun 17 2002

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

NAME

Denominators of coefficients of expansion of arctan(x)^2 = x^2-2/3*x^4+23/45*x^6-44/105*x^8+563/1575*x^10-3254/10395*x^12+ ...

DATA

1, 1, 3, 45, 105, 1575, 10395, 315315, 45045, 6891885, 72747675, 160044885, 1003917915, 21751554825, 35137127025, 2183521465125, 4512611027925, 76714387474725, 40613499251325, 3172365552631275

OFFSET

0,3

CROSSREFS

Cf. A002428.

KEYWORD

nonn,easy,frac

AUTHOR

njas, Jun 17 2002

STATUS

approved