Number of permutations p of 1..n with sum (i-p(i))^2 < (n+1)*n/2.
A179266
Number of permutations p of 1..n with sum (i-p(i))^2 < (n+1)*n/2.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =3a(4) =11a(5) =41a(6) =151a(7) =594a(8) =2667a(9) =13796a(10) =70702a(11) =363135a(12) =2075703a(13) =13050503a(14) =81009240a(15) =499992359a(16) =3350516588a(17) =24169492053a(18) =172363021094
External references
- oeis: A179266