a(n) = (10/11)*(2+9*(-10)^(n-1)).

A165750

a(n) = (10/11)*(2+9*(-10)^(n-1)).

Terms

    a(0) =1a(1) =10a(2) =-80a(3) =820a(4) =-8180a(5) =81820a(6) =-818180a(7) =8181820a(8) =-81818180a(9) =818181820a(10) =-8181818180a(11) =81818181820a(12) =-818181818180

External references