Number of nX3 0..2 arrays with rows and columns lexicographically nondecreasing and every element equal to at least one horizontal or vertical neighbor.

A201534

Number of nX3 0..2 arrays with rows and columns lexicographically nondecreasing and every element equal to at least one horizontal or vertical neighbor.

Terms

    a(0) =3a(1) =25a(2) =111a(3) =633a(4) =3354a(5) =16393a(6) =72811a(7) =293831a(8) =1087857a(9) =3735546a(10) =12012530a(11) =36466979a(12) =105202136a(13) =289996482a(14) =767360174a(15) =1956720113a(16) =4824093641a(17) =11531663892a(18) =26793101230a(19) =60636948110a(20) =133921364986a(21) =289121431541a(22) =611037886807

External references