a(n) = 32*3^n - 2^(n+5) + 5.

Terms

a(0) =5a(1) =37a(2) =165a(3) =613a(4) =2085a(5) =6757a(6) =21285a(7) =65893a(8) =201765a(9) =613477a(10) =1856805a(11) =5603173a(12) =16875045a(13) =50756197a(14) =152530725a(15) =458116453a(16) =1375397925a(17) =4128290917a(18) =12389067045a(19) =37175589733a(20) =111543546405a(21) =334664193637