2071723

Properties

Appears in sequences

• Smallest number with reciprocal of period length n in decimal (base 10).at n=17A003060
• Smallest primitive factor of 10^n - 1. Also smallest prime p such that 1/p has repeating decimal expansion of period n.at n=16A007138
• Triangle of prime numbers in which n-th row lists all primes p such that 1/p has decimal period n, n >= 1.at n=25A046107
• Smallest prime factor of repunit(n) = (10^n-1)/9 (A002275).at n=15A067063
• Divisors of 10^17 - 1.at n=3A113116
• Smallest prime factor of prime(n)-th repunit number.at n=6A147555
• Primes p such that the decimal representation of 1/p does not contain every digit 0-9.at n=38A187614
• Irregular triangle read by rows in which row n lists primitive prime factors of the repunit (10^n - 1)/9 (A002275(n)).at n=26A204845
• Powers of primes other than 2 and 5 in order by cycle length of reciprocal in decimal.at n=28A227969
• Records in A054471.at n=21A243110
• a(n) is the least prime factor > 3 of 10^n - 1.at n=15A366921
• Prime numbersat n=153888