OFFSET
1,1
EXAMPLE
a(1)=2-0=2, a(2)=4-1=3, a(3)=6-3=3, a(4)=12-5=7.
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Nov 14 2009
EXTENSIONS
All numbers > 68 corrected by R. J. Mathar, May 30 2010
STATUS
approved