D-analogs of Bell numbers.

Terms

a(0) =1a(1) =1a(2) =4a(3) =15a(4) =72a(5) =403a(6) =2546a(7) =17867a(8) =137528a(9) =1149079a(10) =10335766a(11) =99425087a(12) =1017259964a(13) =11018905667a(14) =125860969266