Expansion of x^k/Product_{t=k..2k} (1-tx) for k=9.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =0a(9) =1a(10) =135a(11) =10065a(12) =547965a(13) =24336312a(14) =934863930a(15) =32189799070