Ordered Stirling numbers s(n,k) of the second kind.

Terms

a(0) =0a(1) =1a(2) =3a(3) =6a(4) =7a(5) =10a(6) =15a(7) =21a(8) =25a(9) =28a(10) =31a(11) =36a(12) =45a(13) =55a(14) =63a(15) =65a(16) =66a(17) =78a(18) =90a(19) =91a(20) =105a(21) =120a(22) =127a(23) =136a(24) =140a(25) =153a(26) =171a(27) =190a(28) =210a(29) =231