Expansion of e.g.f. -log(1 - x - x^2/2).

Terms

a(0) =1a(1) =2a(2) =5a(3) =21a(4) =114a(5) =780a(6) =6390a(7) =61110a(8) =667800a(9) =8210160a(10) =112152600a(11) =1685237400a(12) =27624920400a(13) =490572482400