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A196688 ((n!)^2-A196687(n))/2. 2


%S 0,0,6,120,4440,157680,9187920,557665920,50759291520,4795586208000,

%T 636749560339200,86796062772249600,15877174512431232000,

%U 2953945462595410483200,712801595188655900928000,173684063741850454560768000,53471242848053479728254976000,16530628080065352033845256192000

%N ((n!)^2-A196687(n))/2.

%C Let p = (p1..pn) and q = (q1..qn) be two random permutations of (1..n); call the pair (p,q) positive if the number of i with pi > qi is greater than the number of i with pi < qi. Then a(n) is the number of positive pairs.

%Y Cf. A062868, A196687. Equals n!*A179567(n).

%K nonn

%O 1,3

%A Jan Lakota, Oct 04 2011

%E a(1)-a(6) computed by Jan Lakota; extended by _N. J. A. Sloane_, Oct 04 2011

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Last modified January 20 11:11 EST 2020. Contains 331083 sequences. (Running on oeis4.)