OFFSET
1,2
COMMENTS
This corresponds to points of positive norm less than or equal to n on the square lattice, in the first quadrant, on or below the first diagonal.
FORMULA
a(n) = A211340 (n) + n . [Joerg Arndt, Aug 19 2013]
CROSSREFS
KEYWORD
nonn
AUTHOR
Olivier Gérard, Aug 17 2013
STATUS
approved