Triangle read by rows: number of order-preserving partial transformations (of an n-element chain) of width and waist both equal to r (width(alpha) = |Dom(alpha)| and waist(alpha) = max(Im(alpha))).
A110858
Triangle read by rows: number of order-preserving partial transformations (of an n-element chain) of width and waist both equal to r (width(alpha) = |Dom(alpha)| and waist(alpha) = max(Im(alpha))).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =1a(7) =3a(8) =6a(9) =6a(10) =1a(11) =4a(12) =12a(13) =24a(14) =20a(15) =1a(16) =5a(17) =20a(18) =60a(19) =100a(20) =70a(21) =1a(22) =6a(23) =30a(24) =120a(25) =300a(26) =420a(27) =252a(28) =1a(29) =7
External references
- oeis: A110858