Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 4 local maxima.
A159718
Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 4 local maxima.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =88a(4) =33600a(5) =3821760a(6) =272509552a(7) =15313310208a(8) =750469872312
External references
- oeis: A159718