These terms given here are based on the comments in A008348 from Dmitry Kamenetsky.
Probably infinite, on probabilistic grounds, but this is an open question. (Comment modified by N. J. A. Sloane, Oct 03 2019.)
Table of n, a(n) for n=1..4.
Cf. A008344, A008348.
Sequence in context: A326618 A154824 A261541 * A137131 A229725 A244113
Adjacent sequences: A309222 A309223 A309224 * A309226 A309227 A309228
N. J. A. Sloane, Aug 31 2019