a(n) = 3*(10^n) + (n^2 + 1)*(10^n - 1)/9.
A137215
a(n) = 3*(10^n) + (n^2 + 1)*(10^n - 1)/9.
Terms
- a(0) =3a(1) =32a(2) =355a(3) =4110a(4) =48887a(5) =588886a(6) =7111107a(7) =85555550a(8) =1022222215a(9) =12111111102a(10) =142222222211
External references
- oeis: A137215