Number of set partitions of [n] such that for each block b the smallest integer interval containing b has at most three elements and for at least one block c the smallest integer interval containing c has exactly three elements.
A320553
Number of set partitions of [n] such that for each block b the smallest integer interval containing b has at most three elements and for at least one block c the smallest integer interval containing c has exactly three elements.
Terms
- a(0) =2a(1) =5a(2) =12a(3) =29a(4) =66a(5) =145a(6) =315a(7) =676a(8) =1436a(9) =3031a(10) =6367a(11) =13323a(12) =27798a(13) =57873a(14) =120281a(15) =249657a(16) =517663a(17) =1072520a(18) =2220724a(19) =4595938a(20) =9508022a(21) =19664296a(22) =40659943a(23) =84057614a(24) =173750589a(25) =359110196a(26) =742150185a(27) =1533651213a(28) =3169118648a(29) =6548358736
External references
- oeis: A320553