Expansion of (1+x)*(1+4*x)/((1-x)*(1-4*x)).

Terms

a(0) =1a(1) =10a(2) =50a(3) =210a(4) =850a(5) =3410a(6) =13650a(7) =54610a(8) =218450a(9) =873810a(10) =3495250a(11) =13981010a(12) =55924050a(13) =223696210a(14) =894784850a(15) =3579139410a(16) =14316557650a(17) =57266230610a(18) =229064922450a(19) =916259689810