The number of partitions of the set [n] where each element can be colored 1 or 2 avoiding the patterns 1^11^2 and 1^22^1 in the pattern sense.
A209797
The number of partitions of the set [n] where each element can be colored 1 or 2 avoiding the patterns 1^11^2 and 1^22^1 in the pattern sense.
Terms
- a(0) =2a(1) =6a(2) =18a(3) =56a(4) =188a(5) =695a(6) =2838a(7) =12726a(8) =62140a(9) =327760a(10) =1854488a(11) =11189273a(12) =71627546a(13) =484332314a(14) =3446042310a(15) =25712613664a(16) =200599911596
External references
- oeis: A209797