OFFSET
1,1
REFERENCES
Mark A. Herkommer, Number Theory, A Programmer's Guide, McGraw-Hill, New York, 1999, page 315.
MATHEMATICA
Select[ Range[206], (Mod[ #, 9] == 0 || Mod[ #, 9] == 1 || Mod[ #, 9] == 4) && !IntegerQ[ Sqrt[ # ]] & ]
Select[Flatten[#+{0, 1, 4}&/@(9*Range[0, 30])], !IntegerQ[Sqrt[#]]&] (* Harvey P. Dale, Dec 29 2019 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Mar 26 2003
STATUS
approved