Triangle of unsigned 4-Lah numbers.

Terms

a(0) =1a(1) =8a(2) =1a(3) =72a(4) =18a(5) =1a(6) =720a(7) =270a(8) =30a(9) =1a(10) =7920a(11) =3960a(12) =660a(13) =44a(14) =1a(15) =95040a(16) =59400a(17) =13200a(18) =1320a(19) =60a(20) =1a(21) =1235520a(22) =926640a(23) =257400a(24) =34320a(25) =2340a(26) =78a(27) =1a(28) =17297280a(29) =15135120