Number of permutations of 2 copies of 1..n with all adjacent differences <= 3 in absolute value.
A177284
Number of permutations of 2 copies of 1..n with all adjacent differences <= 3 in absolute value.
Terms
- a(0) =1a(1) =1a(2) =6a(3) =90a(4) =2520a(5) =41580a(6) =516180a(7) =6068622a(8) =76331906a(9) =958679970a(10) =11679900408a(11) =138047313960
External references
- oeis: A177284