A001135Primes p such that the multiplicative order of 2 modulo p is (p-1)/5.
251, 571, 971, 1181, 1811, 2011, 2381, 2411, 3221, 3251, 3301, 3821, 4211, 4861, 4931, 5021, …
The first term appear at position 1,713.
…390739414333454776241686251898356948556209921922218…
…654448928585291711898800251571032228072299565450345630…
| terms | string | first position | occurrences |
|---|---|---|---|
| 1 | 251 | 1,713 | 1,000,833 |
| 2 | 251571 | 1,149,367 | 991 |
| 3 | 251571971 | not within 1,000,000,000 | 0 |
Searched the first 1,000,000,000 digits. Strings longer than 12 digits are not indexed.