Number of permutations of 1..n with sum (i-p(i))^2 <= n*(n-1)/2.

A179263

Number of permutations of 1..n with sum (i-p(i))^2 <= n*(n-1)/2.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =9a(4) =27a(5) =87a(6) =350a(7) =1675a(8) =7848a(9) =36711a(10) =196510a(11) =1177139a(12) =6908609a(13) =40106433a(14) =256572630a(15) =1785661795a(16) =12221831460a(17) =82732094377a(18) =603846490132

External references