Number of permutations of 2 indistinguishable copies of 1..n with exactly 9 adjacent element pairs in decreasing order.
A151631
Number of permutations of 2 indistinguishable copies of 1..n with exactly 9 adjacent element pairs in decreasing order.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =716a(6) =6030140a(7) =6727188848
External references
- oeis: A151631