OFFSET
1,2
REFERENCES
R. L. Graham et al., On extremal density theorems for linear forms, pp. 103-109 of H. Zassenhaus, editor, Number Theory and Algebra. Academic Press, NY, 1977.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Steven R. Finch, Triple-Free Sets of Integers [From Steven Finch, Apr 20 2019]
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Edited by Steven Finch, Feb 25 2009
Revised by N. J. A. Sloane, Jun 13 2012
a(21) corrected and more terms from Sean A. Irvine, Nov 18 2015
STATUS
approved