Expansion of (1+x)^50 * (1-x)/(1 - x^51).

Terms

a(0) =1a(1) =49a(2) =1175a(3) =18375a(4) =210700a(5) =1888460a(6) =13771940a(7) =83993700a(8) =436994250a(9) =1968555050a(10) =7766844470a(11) =27081460630a(12) =84045912300a(13) =233460867500a(14) =582985137700