a(n) = 4*(10^n - 1).

A086575

a(n) = 4*(10^n - 1).

Terms

    a(0) =0a(1) =36a(2) =396a(3) =3996a(4) =39996a(5) =399996a(6) =3999996a(7) =39999996a(8) =399999996a(9) =3999999996a(10) =39999999996a(11) =399999999996

External references