Number of (n+1) X (1+1) 0..1 arrays with every element equal to some horizontal, vertical or antidiagonal neighbor, with top left element zero.

A232031

Number of (n+1) X (1+1) 0..1 arrays with every element equal to some horizontal, vertical or antidiagonal neighbor, with top left element zero.

Terms

    a(0) =3a(1) =11a(2) =37a(3) =129a(4) =450a(5) =1568a(6) =5464a(7) =19041a(8) =66354a(9) =231230a(10) =805789a(11) =2808009a(12) =9785334a(13) =34099877a(14) =118831060a(15) =414101811a(16) =1443059667a(17) =5028766229a(18) =17524216333a(19) =61068290730a(20) =212810436816a(21) =741600615908

External references