A179958 Number of permutations of 1..n such that |p(i)-p(i-1)| >= 5 for i>1.

1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 160, 6056, 161136, 3661824, 76972416, 1572313392, 32096768008, 665456850864, 14144815265510, 309931658271656, 7021414359095808

Offset: 0

Author

R. H. Hardin, Aug 03 2010

Keywords

• nonn

Comments

Permutations such that the absolute difference between adjacent elements is at least 5.

Extensions

a(0), a(19)-a(20) from Alois P. Heinz, Oct 27 2014

a(21) from Alois P. Heinz, Feb 10 2025