a(1) = 1; for n > 1, a(n) is the smallest prime divisor of the number formed by the concatenation of a(1) to a(n-1) that has not previously appeared in the sequence.

A330291

a(1) = 1; for n > 1, a(n) is the smallest prime divisor of the number formed by the concatenation of a(1) to a(n-1) that has not previously appeared in the sequence.