Number of permutations p of 1..n with sum (i-p(i))^2 <= (n+1)*n/2.
A179264
Number of permutations p of 1..n with sum (i-p(i))^2 <= (n+1)*n/2.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =13a(5) =41a(6) =151a(7) =672a(8) =3047a(9) =13796a(10) =70702a(11) =406241a(12) =2306597a(13) =13050503a(14) =81009240a(15) =546463298a(16) =3646507024a(17) =24169492053a(18) =172363021094
External references
- oeis: A179264