Number of length n+3 0..3 arrays with no four elements in a row with pattern abba (possibly a=b) and new values 0..3 introduced in 0..3 order.
A243028
Number of length n+3 0..3 arrays with no four elements in a row with pattern abba (possibly a=b) and new values 0..3 introduced in 0..3 order.
Terms
- a(0) =13a(1) =42a(2) =147a(3) =536a(4) =1987a(5) =7414a(6) =27736a(7) =103868a(8) =389129a(9) =1458054a(10) =5463618a(11) =20473754a(12) =76721788a(13) =287502448a(14) =1077370309a(15) =4037278442a(16) =15129079265a(17) =56693899710a(18) =212451684345a(19) =796130077586
External references
- oeis: A243028