Expansion of (1-x)*(1-2*x)/(1-5*x+5*x^2).

Terms

a(0) =1a(1) =2a(2) =7a(3) =25a(4) =90a(5) =325a(6) =1175a(7) =4250a(8) =15375a(9) =55625a(10) =201250a(11) =728125a(12) =2634375a(13) =9531250a(14) =34484375a(15) =124765625a(16) =451406250a(17) =1633203125a(18) =5908984375a(19) =21378906250a(20) =77349609375a(21) =279853515625