OFFSET
0,2
COMMENTS
Each positive integer can be represented exactly once as the difference of two terms.
LINKS
Paul Erdõs, Problem E3202, American Mathematical Monthly, 94(1987), 372. [N. Sato, Oct 14 2008]
EXAMPLE
a(4) = 2*a(3)+1 = 15,
a(5) = a(4)+7 = 22 because 7 is not yet a difference.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Holger Stephan (stephan(AT)wias-berlin.de), Nov 04 2005
EXTENSIONS
Edited by Don Reble, May 16 2006
Definition corrected by Guy P. Srinivasan, Dec 11 2006
STATUS
approved