Number of nX3 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and every element equal to zero or two horizontal or vertical neighbors.
A199241
Number of nX3 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and every element equal to zero or two horizontal or vertical neighbors.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =25a(4) =110a(5) =472a(6) =2080a(7) =9279a(8) =41704a(9) =187500a(10) =853012a(11) =3919309a(12) =18163022a(13) =84589504a(14) =395762792a(15) =1858908001a(16) =8762833946a(17) =41439737234a(18) =196527899276a(19) =934460643457
External references
- oeis: A199241