Number of permutations of 1..n with the Sum_{i=1..n} of (i-p(i))^2 < (n-1)*n*(n+1)/6.
A180112
Number of permutations of 1..n with the Sum_{i=1..n} of (i-p(i))^2 < (n-1)*n*(n+1)/6.
Terms
- a(0) =1a(1) =3a(2) =11a(3) =57a(4) =360a(5) =2428a(6) =19692a(7) =178096a(8) =1814400a(9) =19748160a(10) =237351468a(11) =3091307829a(12) =43589145600a(13) =650470873262
External references
- oeis: A180112