a(n) = 4*(10^n-5).

A177109

a(n) = 4*(10^n-5).

Terms

    a(0) =20a(1) =380a(2) =3980a(3) =39980a(4) =399980a(5) =3999980a(6) =39999980a(7) =399999980a(8) =3999999980a(9) =39999999980a(10) =399999999980

External references