OFFSET
1,6
LINKS
Boris Gourevitch, Graph of A083057
FORMULA
a(n) = n/3 + O(n) (it seems O(n) could be replaced with O(log(n))).
PROG
(PARI) {a(n)=if(n<1, 0, sum(k=1, n, sqrtint(3*k^2)-3*sqrtint(k^2\3)==1))} /* Michael Somos, Aug 31 2006 */
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Apr 18 2003
STATUS
approved