Number of nX1 0..4 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor.

A203184

Number of nX1 0..4 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor.

Terms

    a(0) =1a(1) =5a(2) =25a(3) =95a(4) =325a(5) =1121a(6) =3985a(7) =14288a(8) =50995a(9) =181336a(10) =644721a(11) =2294193a(12) =8166441a(13) =29066618a(14) =103444256a(15) =368138471a(16) =1310164527a(17) =4662787112a(18) =16594519920a(19) =59058487061a(20) =210183969235a(21) =748026706926

External references