Number of (n+2) X (1+2) 0..2 arrays with every 3 X 3 subblock row and column sum 2 3 or 4 and every diagonal and antidiagonal sum not 2 3 or 4.

A252221

Number of (n+2) X (1+2) 0..2 arrays with every 3 X 3 subblock row and column sum 2 3 or 4 and every diagonal and antidiagonal sum not 2 3 or 4.

Terms

    a(0) =228a(1) =368a(2) =812a(3) =1442a(4) =2458a(5) =4738a(6) =9922a(7) =20070a(8) =38774a(9) =75106a(10) =148914a(11) =296946a(12) =586790a(13) =1153474a(14) =2273494a(15) =4495766a(16) =8887778a(17) =17542298a(18) =34612226a(19) =68336662a(20) =134968250a(21) =266516414a(22) =526161790a(23) =1038785394a(24) =2051072242a(25) =4049909170a(26) =7996310710

External references