Klarner-Rado Sequence

The thinnest sequence which contains 1, and whenever it contains $x$, also contains $2x$, $3x+2$, and $6x+3$: 1, 2, 4, 5, 8, 9, 10, 14, 15, 16, 17, ... (Sloane's A005658).

References

Guy, R. K. ``Klarner-Rado Sequences.'' §E36 in Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, p. 237, 1994.

Klarner, D. A. and Rado, R. ``Linear Combinations of Sets of Consecutive Integers.'' Amer. Math. Monthly 80, 985-989, 1973.

Sloane, N. J. A. Sequence A005658/M0969 in ``An On-Line Version of the Encyclopedia of Integer Sequences.'' http://www.research.att.com/~njas/sequences/eisonline.html and Sloane, N. J. A. and Plouffe, S. The Encyclopedia of Integer Sequences. San Diego: Academic Press, 1995.