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Number of permutations of 1..n with the Sum_{i=1..n} of (i-p(i))^2 < (n-1)*n*(n+1)/6.
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%I #17 Jul 23 2017 07:42:09

%S 1,3,11,57,360,2428,19692,178096,1814400,19748160,237351468,

%T 3091307829,43589145600,650470873262,10415387654044,177171175431551,

%U 3201186852864000,60647963017860105,1213361365706836584,25488014447816087399,562000363888803840000

%N Number of permutations of 1..n with the Sum_{i=1..n} of (i-p(i))^2 < (n-1)*n*(n+1)/6.

%F a(n) = A000142(n)/2 - A056876(n)/2. - _Alois P. Heinz_, May 07 2013

%K nonn

%O 2,2

%A _R. H. Hardin_, Aug 10 2010

%E a(16)-a(19) from _Robert Gerbicz_, Nov 27 2010

%E a(20)-a(22) from _Alois P. Heinz_, May 07 2013