Number of set partitions of [n] having exactly four pairs (m,m+1) such that m is in some block b and m+1 is in block b+1.
A271791
Number of set partitions of [n] having exactly four pairs (m,m+1) such that m is in some block b and m+1 is in block b+1.
Terms
- a(0) =0a(1) =1a(2) =15a(3) =129a(4) =891a(5) =5611a(6) =34213a(7) =208230a(8) =1285094a(9) =8108722a(10) =52540098a(11) =350375379a(12) =2407395908a(13) =17048774736a(14) =124435165429a(15) =935736058614
External references
- oeis: A271791