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

Terms

a(0) =7a(1) =67a(2) =727a(3) =7987a(4) =87847a(5) =966307a(6) =10629367a(7) =116923027a(8) =1286153287a(9) =14147686147a(10) =155624547607