Expansion of ((1-x)/(1-2*x))^4.

Terms

a(0) =1a(1) =4a(2) =14a(3) =44a(4) =129a(5) =360a(6) =968a(7) =2528a(8) =6448a(9) =16128a(10) =39680a(11) =96256a(12) =230656a(13) =546816a(14) =1284096a(15) =2990080a(16) =6909952a(17) =15859712a(18) =36175872a(19) =82051072a(20) =185139200a(21) =415760384a(22) =929562624a(23) =2069889024a(24) =4591714304a(25) =10150215680a(26) =22364028928a(27) =49123688448a(28) =107592286208a(29) =235015241728