a(n) = 2^(n-1)*(5*n-8) + 5.

Terms

a(0) =1a(1) =2a(2) =9a(3) =33a(4) =101a(5) =277a(6) =709a(7) =1733a(8) =4101a(9) =9477a(10) =21509a(11) =48133a(12) =106501a(13) =233477a(14) =507909a(15) =1097733a(16) =2359301a(17) =5046277a(18) =10747909a(19) =22806533a(20) =48234501a(21) =101711877a(22) =213909509a(23) =448790533a(24) =939524101a(25) =1962934277a(26) =4093640709a(27) =8522825733a(28) =17716740101a(29) =36775657477