A081642 Integers congruent to 0, 1 or 4 (mod 9) which are not squares.

10, 13, 18, 19, 22, 27, 28, 31, 37, 40, 45, 46, 54, 55, 58, 63, 67, 72, 73, 76, 82, 85, 90, 91, 94, 99, 103, 108, 109, 112, 117, 118, 126, 127, 130, 135, 136, 139, 145, 148, 153, 154, 157, 162, 163, 166, 171, 172, 175, 180, 181, 184, 189, 190, 193, 198, 199, 202

Offset: 1

Author

Robert G. Wilson v, Mar 26 2003

Keywords

• easy
• nonn

References

• Mark A. Herkommer, Number Theory, A Programmer's Guide, McGraw-Hill, New York, 1999, page 315.

Crossrefs

Cf. A028837.

Programs

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 *)