Octuple factorial, 8-factorial, n!8, n!!!!!!!!.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =6a(7) =7a(8) =8a(9) =9a(10) =20a(11) =33a(12) =48a(13) =65a(14) =84a(15) =105a(16) =128a(17) =153a(18) =360a(19) =627a(20) =960a(21) =1365a(22) =1848a(23) =2415a(24) =3072a(25) =3825a(26) =9360a(27) =16929a(28) =26880a(29) =39585