= = = PRIME NUMBERS OF THE FORM A * 14^B - 1 = = =

Computed by John Eisenmann

The numbers listed on this page have the form A * 14^B - 1, where A and B are integers such that 0 < A < 14 and B > 0. In base 14, these numbers consist of a digit followed by at least one D. For example: 1D, 2D, 3D, 4D, 4DD, and 4,DDD.

I am looking for values of A and B such that A * 14^B - 1 is prime.

I used a custom-made program to search for these prime numbers. This program is networked across many computational nodes. The program uses the GMP arithmetic library and the Miller-Rabin primality test. These primes are marked as "Industrial Primes".

In addition, I have performed deterministic tests on some of the industrial primes. For numbers where B <= 1912, I used the Ellipsa Primo application which Dana kindly introduced to me. For numbers where B > 1912, I used my own implementation of the N + 1 algorithm described in a paper by John Brillhart, D. H. Lehmer, and J. L. Selfridge. This implementation uses an algorithm by Victor Shoup to calculate Jacobi symbols, and a formula from mathworld.wolfram.com to calculate Lucas sequences.

All of the numbers I have tested in a deterministic fashion have passed, and have been marked as "Definitely Prime".

Current status of the search program:

Working on candidate 12 * 14^56141 - 1 (base 9885 / 18649)

Currently active computational nodes:

Beryllium2
Beryllium1

Below are all of the A * 14^B - 1 primes I (we?) have found:

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