Number of permutations p() of 1..n+4 with centered difference p(i+1)-p(i-1) < 0 exactly 3 times.
A180881
Number of permutations p() of 1..n+4 with centered difference p(i+1)-p(i-1) < 0 exactly 3 times.
Terms
- a(0) =10a(1) =160a(2) =1960a(3) =17080a(4) =130914a(5) =877968a(6) =5517204a(7) =32369568a(8) =183346020a(9) =997586304a(10) =5324138820a(11) =27695982600a(12) =142629565650a(13) =721661798000
External references
- oeis: A180881