Triangle of generalized Stirling numbers.

Terms

a(0) =1a(1) =1a(2) =4a(3) =1a(4) =27a(5) =36a(6) =1a(7) =172a(8) =864a(9) =576a(10) =1a(11) =1125a(12) =17500a(13) =36000a(14) =14400a(15) =1a(16) =7591a(17) =351000a(18) =1746000a(19) =1944000a(20) =518400a(21) =1a(22) =52479a(23) =7197169a(24) =80262000a(25) =191394000a(26) =133358400a(27) =25401600a(28) =1a(29) =369580