Expansion of e.g.f. Product_{k>=1} (1 + x^k/k!)^(k-1).

Terms

a(0) =1a(1) =0a(2) =1a(3) =2a(4) =3a(5) =24a(6) =70a(7) =300a(8) =1365a(9) =10136a(10) =48636a(11) =253560a(12) =2069430a(13) =13716780a(14) =107972579a(15) =695118606a(16) =6155201325a(17) =53001340112a(18) =483401450344