a(n) = 7*8^n+1.

Terms

a(0) =8a(1) =57a(2) =449a(3) =3585a(4) =28673a(5) =229377a(6) =1835009a(7) =14680065a(8) =117440513a(9) =939524097a(10) =7516192769a(11) =60129542145a(12) =481036337153