a(n) = 5*12^n - 1.

A199107

a(n) = 5*12^n - 1.

Terms

    a(0) =4a(1) =59a(2) =719a(3) =8639a(4) =103679a(5) =1244159a(6) =14929919a(7) =179159039a(8) =2149908479a(9) =25798901759a(10) =309586821119

External references