A028794 Nonsquares mod 81.

2, 3, 5, 6, 8, 11, 12, 14, 15, 17, 18, 20, 21, 23, 24, 26, 27, 29, 30, 32, 33, 35, 38, 39, 41, 42, 44, 45, 47, 48, 50, 51, 53, 54, 56, 57, 59, 60, 62, 65, 66, 68, 69, 71, 72, 74, 75, 77, 78, 80

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• fini
• full
• easy

Crossrefs

Cf. A010442.

Programs

Mathematica

Complement[Range[0, 80], PowerMod[Range[81], 2, 81]] (* Alonso del Arte, Dec 27 2019 *)

Scala

(0 to 80).diff((1 to 81).map(n => (n * n) % 81)) // Alonso del Arte, Dec 27 2019