

A138896


Ratio of (2n1)! to number of zeros in Sylvester matrix of polynomial of n degree with all nonzero coefficients.


2



3, 15, 280, 11340, 798336, 86486400, 13343616000, 2778808032000, 750895681536000, 255454710858547200, 106826515449937920000, 53858368206010368000000, 32215590089995124736000000
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OFFSET

2,1


COMMENTS

(2n1)! = A009445 = number of monomials in determinant of symbolic square matrix of size 2n1 X 2n1 without zeros.


LINKS

Table of n, a(n) for n=2..14.


FORMULA

a(n)=(2 n  1)!/(2 (n  1)^2) (n=2,3,4,...)


MATHEMATICA

Table[(2 n  1)!/(2 (n  1)^2), {n, 2, 20}]


CROSSREFS

Cf. A001105, A009445, A007878.
Sequence in context: A013353 A270401 A270001 * A090627 A070234 A036279
Adjacent sequences: A138893 A138894 A138895 * A138897 A138898 A138899


KEYWORD

nonn


AUTHOR

Artur Jasinski, Apr 02 2008


STATUS

approved



