The number of partitions of the set [n] where each element can be colored 1 or 2 avoiding the patterns 1^12^2 and 1^22^1 in the pattern sense.
A209629
The number of partitions of the set [n] where each element can be colored 1 or 2 avoiding the patterns 1^12^2 and 1^22^1 in the pattern sense.
Terms
- a(0) =2a(1) =6a(2) =16a(3) =44a(4) =134a(5) =468a(6) =1880a(7) =8534a(8) =42804a(9) =232972a(10) =1359186a(11) =8431288a(12) =55297064a(13) =381815026a(14) =2765949856a(15) =20960349828a(16) =165729870678
External references
- oeis: A209629