Related to sorting procedure studied by West: number of permutations that are both sorted (i.e., obtainable as output of the sorting procedure) and one-stack sortable.
A027432
Related to sorting procedure studied by West: number of permutations that are both sorted (i.e., obtainable as output of the sorting procedure) and one-stack sortable.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =10a(6) =25a(7) =69a(8) =192a(9) =562a(10) =1663a(11) =5065a(12) =15592a(13) =48874a(14) =154651a(15) =495418a(16) =1599816a(17) =5212650a(18) =17098590a(19) =56473664a(20) =187572584a(21) =626430568a(22) =2101977231a(23) =7084963950a(24) =23976649328a(25) =81447876258a(26) =277627821135a(27) =949393445553
External references
- oeis: A027432