Expansion of Sum_{k>=0} (-2)^k * x^(2*k)/Product_{j=1..k} (1 - j * x).

Terms

a(0) =1a(1) =0a(2) =-2a(3) =-2a(4) =2a(5) =10a(6) =18a(7) =10a(8) =-62a(9) =-310a(10) =-894a(11) =-1590a(12) =642a(13) =21514a(14) =120322a(15) =461130a(16) =1230466a(17) =877194a(18) =-16158974a(19) =-142301750a(20) =-798423166a(21) =-3397990646a(22) =-9764986878a(23) =2009650762a(24) =294960691330