a(n) = 6*(10^(2*n+1)-1)/9 - 5*10^n.A332161a(n) = 6*(10^(2*n+1)-1)/9 - 5*10^n.Terms a(0) =1a(1) =616a(2) =66166a(3) =6661666a(4) =666616666a(5) =66666166666External referencesoeis: A332161