OFFSET
0,3
COMMENTS
b(n) can be as large as 2^n. [From Max Alekseyev, May 10 2009]
EXAMPLE
For n=3, the sequences are 1,2,3,4; 1,2,3,6; 1,2,4,5; 1,2,4,6; and 1,2,4,8. We can't have 1,2,3,5 because the difference (5-3) does not divide 3.
CROSSREFS
KEYWORD
nonn
AUTHOR
Franklin T. Adams-Watters, Aug 25 2006
EXTENSIONS
a(15)..a(21) from Max Alekseyev, May 10 2009
STATUS
approved