Number of permutations of 4 indistinguishable copies of 1..n with exactly 3 adjacent element pairs in decreasing order.
A151641
Number of permutations of 4 indistinguishable copies of 1..n with exactly 3 adjacent element pairs in decreasing order.
Terms
- a(0) =0a(1) =16a(2) =8464a(3) =724320a(4) =37229920a(5) =1558185200a(6) =59416090096
External references
- oeis: A151641