Let a(1) = 1. Given a(1), ..., a(2^t), find the least k such that a(1) + 2^k, a(2) + 2^k, ..., a(2^t) + 2^k are all composite and a(1) + 2^k > a(2^t). Then a(2^t+i) = a(i) + 2^k for all 1 <= i <= 2^t.

A173281

Let a(1) = 1. Given a(1), ..., a(2^t), find the least k such that a(1) + 2^k, a(2) + 2^k, ..., a(2^t) + 2^k are all composite and a(1) + 2^k > a(2^t). Then a(2^t+i) = a(i) + 2^k for all 1 <= i <= 2^t.