Expansion of e.g.f. (1 - x^3)^(-1/x).

Terms

a(0) =1a(1) =0a(2) =2a(3) =0a(4) =12a(5) =60a(6) =120a(7) =2520a(8) =15120a(9) =90720a(10) =1693440a(11) =13305600a(12) =140374080a(13) =2724321600a(14) =27744837120a(15) =414096883200