2020-01-09, 11:56 | #1 |
Mar 2018
1000001111_{2} Posts |
Congruent to 10^n mod 41
215, 51456, 69660, 92020 and 541456 are the k's such that pg(k) is prime and k is congruent to 10^n mod 41 for n some nonneg integer
I think it is surprising that in the case k is NOT a multiple of 3 (k=215, 92020, 541456) Then (k-10^n)/41 is a number A such that inserting a 0 in each pair of adjacent digits it turns out to be a multiple of A. Example (541456-10)/41=13206. Inserting a 0 in each pair of adiajent dig its you have 103020006 which is a multiple of 13206. The thing doesn't work when k is a multiple of 3 as in the cases 69660 and 51456 Last fiddled with by enzocreti on 2020-01-09 at 12:09 |
Thread Tools | |
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Pg primes congruent to 1111 mod 42^2 | enzocreti | enzocreti | 0 | 2019-06-27 12:31 |
((my) mod n ) congruent to n-1 | smslca | Math | 2 | 2012-01-29 11:30 |