999999000001
domain: N
Appears in sequences
- Largest prime factor of 10^n + 1.at n=18A003021
- Smallest primitive factor of 10^n - 1. Also smallest prime p such that 1/p has repeating decimal expansion of period n.at n=35A007138
- Primes with unique period length (the periods are given in A007498).at n=11A007615
- Prime 3 followed by unique period primes (the period r of 1/p is not shared with any other prime) of the form A019328(r)/gcd(A019328(r),r) in order (periods r are given in A051627).at n=9A040017
- Numbers m such that m^2 is a concatenation of two consecutive decreasing numbers.at n=15A054216
- a(n) = n^12 - n^6 + 1.at n=10A060896
- Multipliers resulting from A068665.at n=16A068972
- Largest prime factor of 10^(6*n) + 1.at n=2A072848
- Prime numbers p such that p^2 is a concatenation of decimal representations of m and m-1 for some integer m.at n=2A145381
- Primes p such that p^2 divides p.p.p where dot "." means concatenation.at n=6A147554
- a(n) = 1 - 10^n + 100^n.at n=6A168624
- Primes of the form k^6 - k^3 + 1.at n=11A175170
- Primes of the form 100^k - 10^k + 1.at n=2A187868
- a(n) is the greatest prime divisor of 10^(2*n)+10^n+1.at n=11A190839
- Largest prime factor of A138148(n).at n=16A269503
- Primes of the form Phi(k, -10), where Phi is the cyclotomic polynomial.at n=7A291990
- Primes of the form Phi(k, 10), where Phi is the cyclotomic polynomial.at n=8A292014