9998999

Appears in sequences

• Terms of A088753 that are not terms of A063048.at n=9A089521
• Expansion of (1-x+x^2)/((x^2+x+1)*(x^2+5*x+1)).at n=10A110310
• a(n) = 10^(2*n+1) - 10^n - 1.at n=3A181965