Number of permutations of 2 indistinguishable copies of 1..n with exactly 6 adjacent element pairs in decreasing order.
A151628
Number of permutations of 2 indistinguishable copies of 1..n with exactly 6 adjacent element pairs in decreasing order.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =1a(4) =5158a(5) =1822014a(6) =242384856a(7) =19323413187
External references
- oeis: A151628