a(n) = 20*a(n-1) - a(n-2).

A001085

a(n) = 20*a(n-1) - a(n-2).

Terms

    a(0) =1a(1) =10a(2) =199a(3) =3970a(4) =79201a(5) =1580050a(6) =31521799a(7) =628855930a(8) =12545596801a(9) =250283080090

External references