Number of permutations of 2 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 3.
A190824
Number of permutations of 2 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 3.
Terms
- a(0) =1a(1) =0a(2) =0a(3) =0a(4) =1a(5) =20a(6) =292a(7) =4317a(8) =69862a(9) =1251584a(10) =24728326a(11) =535333713a(12) =12616277612a(13) =321762301156
External references
- oeis: A190824