Expansion of (3+x)/(1-x)^6.

Terms

a(0) =3a(1) =19a(2) =69a(3) =189a(4) =434a(5) =882a(6) =1638a(7) =2838a(8) =4653a(9) =7293a(10) =11011a(11) =16107a(12) =22932a(13) =31892a(14) =43452a(15) =58140a(16) =76551a(17) =99351a(18) =127281a(19) =161161a(20) =201894a(21) =250470a(22) =307970a(23) =375570a(24) =454545a(25) =546273a(26) =652239a(27) =774039a(28) =913384a(29) =1072104