49999999999
domain: N
Appears in sequences
- Smallest semiprime containing exactly n 9's.at n=9A104775
- Smallest semiprime ending in exactly n 9's.at n=9A106663
- Numbers that are the sum or product of two numbers, such that the sum and product have reversed digits.at n=24A166749
- Numbers n such that (n+n+1) divides the decimal concatenation [n, n+1].at n=21A173712
- a(n) = 5*10^n - 1.at n=10A198971
- a(n) = 2^(n mod 2)*5*10^floor(n/2) - 1.at n=20A268099