Triangle of generalized Stirling numbers S_{3,3}(n,k) read by rows (n>=1, 3<=k<=3n).

Terms

a(0) =1a(1) =6a(2) =18a(3) =9a(4) =1a(5) =36a(6) =540a(7) =1242a(8) =882a(9) =243a(10) =27a(11) =1a(12) =216a(13) =13608a(14) =94284a(15) =186876a(16) =149580a(17) =56808a(18) =11025a(19) =1107a(20) =54a(21) =1a(22) =1296a(23) =330480a(24) =6148872a(25) =28245672a(26) =49658508a(27) =41392620a(28) =18428400a(29) =4691412