Iterates of the Riesel problem starting at 509203.
509203, 1018407, 2036815, 4073631, 8147263, 16294527, 32589055, 65178111, 130356223, 260712447, 521424895, 1042849791, 2085699583, 4171399167, 8342798335, 16685596671, 33371193343, 66742386687, 133484773375, 266969546751, 533939093503, 1067878187007
0
Given one term x, the next term is 2*x+1. After the zeroth term, the prime 509203, it can be proved that all terms are composite. It is conjectured that 509203 is the smallest such number.
T. D. Noe, Plot of 301 terms
T. D. Noe, Table of 301 terms
Eric W. Weisstein, MathWorld: Riesel Number
(Mma) k = 509203; Table[(k+1) * 2^n - 1, {n, 0, 30}]
nonn
T. D. Noe, May 13 2015