The triangle T_2(n, m), where T_2(n, m) is the number of surjective multi-valued functions from {1, 1, 2, 3, ..., n-1} to {1, 2, 3, ..., m} by rows (n >= 1, 1 <= m <= n).
A172106
The triangle T_2(n, m), where T_2(n, m) is the number of surjective multi-valued functions from {1, 1, 2, 3, ..., n-1} to {1, 2, 3, ..., m} by rows (n >= 1, 1 <= m <= n).
Terms
- a(0) =0a(1) =1a(2) =1a(3) =1a(4) =4a(5) =3a(6) =1a(7) =10a(8) =21a(9) =12a(10) =1a(11) =22a(12) =93a(13) =132a(14) =60a(15) =1a(16) =46a(17) =345a(18) =900a(19) =960a(20) =360a(21) =1a(22) =94a(23) =1173a(24) =4980a(25) =9300a(26) =7920a(27) =2520a(28) =1a(29) =190
External references
- oeis: A172106