Number of set partitions of [n] such that for each pair of consecutive blocks (b,b+1) at least one pair of consecutive numbers (i,i+1) exists with i member of b and i+1 member of b+1.
A271270
Number of set partitions of [n] such that for each pair of consecutive blocks (b,b+1) at least one pair of consecutive numbers (i,i+1) exists with i member of b and i+1 member of b+1.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =14a(5) =43a(6) =145a(7) =536a(8) =2157a(9) =9371a(10) =43630a(11) =216397a(12) =1137703a(13) =6313675a(14) =36848992a(15) =225464838a(16) =1442216870a(17) =9620746697a(18) =66781675113a(19) =481413175433
External references
- oeis: A271270