Number of permutations of 2 indistinguishable copies of 1..n with exactly 5 adjacent element pairs in decreasing order.
A151627
Number of permutations of 2 indistinguishable copies of 1..n with exactly 5 adjacent element pairs in decreasing order.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =72a(4) =27664a(5) =2864328a(6) =163809288a(7) =6727188848a(8) =225167210712
External references
- oeis: A151627