Generalized Bell numbers.

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =19a(5) =101a(6) =1776a(7) =23717a(8) =515971a(9) =11893597a(10) =346475728a(11) =11497161545a(12) =444592761746