Number of set partitions of [n] having exactly two pairs (m,m+1) such that m is in some block b and m+1 is in block b+1.
A271789
Number of set partitions of [n] having exactly two 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) =6a(3) =24a(4) =86a(5) =307a(6) =1143a(7) =4513a(8) =18956a(9) =84546a(10) =399218a(11) =1989792a(12) =10439521a(13) =57504306a(14) =331747730a(15) =1999924893a(16) =12571830681a(17) =82245682149a(18) =558951842996
External references
- oeis: A271789