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A191011 E.g.f. log(1 + sin(arctan(x))). 0
0, 1, -1, -1, 6, 9, -120, -225, 5040, 11025, -362880, -893025, 39916800, 108056025, -6227020800, -18261468225, 1307674368000, 4108830350625, -355687428096000, -1187451971330625, 121645100408832000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

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

FORMULA

a(n) = n!*sum(m=0..(n-1)/2, binomial((n-2)/2,m)*(-1)^(n-m-1)/(n-2*m)), n>0.

MATHEMATICA

With[{nn=30}, CoefficientList[Series[Log[1+Sin[ArcTan[x]]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Sep 19 2011 *)

PROG

(Maxima)

a(n):=n!*sum(binomial((n-2)/2, m)*(-1)^(n-m-1)/(n-2*m), m, 0, (n-1)/2);

CROSSREFS

Sequence in context: A103107 A121233 A156180 * A053490 A265383 A264375

Adjacent sequences:  A191008 A191009 A191010 * A191012 A191013 A191014

KEYWORD

sign

AUTHOR

Vladimir Kruchinin, Jun 16 2011

STATUS

approved

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Last modified July 24 01:41 EDT 2021. Contains 346269 sequences. (Running on oeis4.)