5179

This number is a prime.

A generalized arithmetic progression of primes (a GAP) is a set of integers of the form

a + n₁b₁ + n₂b₂ + ... + n_db_d

with a, b₁, b₂, ..., b_d fixed; and the n's run through some range. The table below shows the smallest 2-by-k GAP's (those with the least last term) for small k. When k is 9, the largest term is 5179.

k            GAP        Last Term
2          3+8i+2j             13
3          7+24i+6j            43
4          5+36i+6j            59
5         11+96i+30j          227
6         11+42i+60j          353
7        47+132i+210j        1439
8       199+3300i+210j       4969
9       199+3300i+210j       5179

[Granville]