Number of permutations of 1..n with no adjacent pair summing to n + 9.
A173849
Number of permutations of 1..n with no adjacent pair summing to n + 9.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =120a(6) =720a(7) =5040a(8) =40320a(9) =362880a(10) =2903040a(11) =32659200a(12) =333849600a(13) =4470681600a(14) =55244851200a(15) =855496857600
External references
- oeis: A173849