a(n) = 11*6^n - 1.

Terms

a(0) =10a(1) =65a(2) =395a(3) =2375a(4) =14255a(5) =85535a(6) =513215a(7) =3079295a(8) =18475775a(9) =110854655a(10) =665127935a(11) =3990767615a(12) =23944605695a(13) =143667634175a(14) =862005805055