Number of nX1 0..3 arrays with values 0..3 introduced in row major order, the number of instances of each value within one of each other, and every element equal to one or two horizontal or vertical neighbors.
A199358
Number of nX1 0..3 arrays with values 0..3 introduced in row major order, the number of instances of each value within one of each other, and every element equal to one or two horizontal or vertical neighbors.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =1a(8) =4a(9) =6a(10) =4a(11) =1a(12) =10a(13) =45a(14) =105a(15) =105a(16) =735a(17) =1935a(18) =2270a(19) =1001a(20) =8854a(21) =30961a(22) =50669a(23) =32706a(24) =268440a(25) =834720a(26) =1164240a(27) =614040a(28) =5334840a(29) =17805870
External references
- oeis: A199358