a(0) = 9, a(n) = 2*a(n-1) + 2^(n-1) for n > 0.

Terms

a(0) =9a(1) =19a(2) =40a(3) =84a(4) =176a(5) =368a(6) =768a(7) =1600a(8) =3328a(9) =6912a(10) =14336a(11) =29696a(12) =61440a(13) =126976a(14) =262144a(15) =540672a(16) =1114112a(17) =2293760a(18) =4718592a(19) =9699328a(20) =19922944a(21) =40894464a(22) =83886080a(23) =171966464a(24) =352321536a(25) =721420288a(26) =1476395008a(27) =3019898880a(28) =6174015488a(29) =12616466432