OFFSET
0,2
EXAMPLE
For n=0..2, there is 1 root. For n=3..6, there are 3 roots. For n=7..9, there are 5 roots. etc... So first ranks are 0,3,7,10, ...
CROSSREFS
KEYWORD
nonn
AUTHOR
Sébastien Dumortier, Sep 28 2008
STATUS
approved