Number of permutations of 2 copies of 1..n with all adjacent differences <= 6 in absolute value.
A177287
Number of permutations of 2 copies of 1..n with all adjacent differences <= 6 in absolute value.
Terms
- a(0) =1a(1) =1a(2) =6a(3) =90a(4) =2520a(5) =113400a(6) =7484400a(7) =681080400a(8) =46118872800
External references
- oeis: A177287