A028733 Nonsquares mod 20.

2, 3, 6, 7, 8, 10, 11, 12, 13, 14, 15, 17, 18, 19

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• fini
• full
• easy

Crossrefs

Cf. A010382.

Programs

Mathematica

Complement[Range[0, 19], PowerMod[Range[20], 2, 20]] (* Alonso del Arte, Dec 20 2019 *)

Scala

(0 to 19).diff((1 to 20).map(n => (n * n) % 20)) // Alonso del Arte, Dec 20 2019