T(n,k) = Stirling2(n,k) * OrderedBell(k).

Terms

a(0) =1a(1) =1a(2) =3a(3) =1a(4) =9a(5) =13a(6) =1a(7) =21a(8) =78a(9) =75a(10) =1a(11) =45a(12) =325a(13) =750a(14) =541a(15) =1a(16) =93a(17) =1170a(18) =4875a(19) =8115a(20) =4683a(21) =1a(22) =189a(23) =3913a(24) =26250a(25) =75740a(26) =98343a(27) =47293a(28) =1a(29) =381