168422domain: NAppears in sequencesNumber T(n,k) of tilings of a 5 X n rectangle with pentominoes of any shape and exactly k pentominoes of shape V; triangle T(n,k), n>=0, 0<=k<=max(0,n-2+delta_{n,3}), read by rows.at n=26A247709Number of permutations of [n] avoiding {4231, 2143, 1234}.at n=23A294708