Number of permutations of 4 indistinguishable copies of 1..n arranged in a circle with exactly 4 adjacent element pairs in decreasing order.
A151599
Number of permutations of 4 indistinguishable copies of 1..n arranged in a circle with exactly 4 adjacent element pairs in decreasing order.
Terms
- a(0) =0a(1) =2a(2) =13485a(3) =2273540a(4) =167274075a(5) =8894295174a(6) =406137173897
External references
- oeis: A151599