A028755 Nonsquares mod 42.

2, 3, 5, 6, 8, 10, 11, 12, 13, 14, 17, 19, 20, 23, 24, 26, 27, 29, 31, 32, 33, 34, 35, 38, 40, 41

Offset

1,1

Links

Table of n, a(n) for n=1..26.

Mathematica

Complement[Range[0, 41], PowerMod[Range[42], 2, 42]] (* Alonso del Arte, Dec 21 2019 *)

Prog

(PARI) for(k=0, 42, if(!issquare(Mod(k, 42)), print1(k, ", "))) \\ Hugo Pfoertner, Dec 02 2019
(Scala) (0 to 41).diff((1 to 42).map(n => (n * n) % 42)) // Alonso del Arte, Dec 21 2019

Crossrefs

Cf. A010403.

Sequence in context: A283513 A028776 A028734 * A187897 A187319 A095976

Adjacent sequences: A028752 A028753 A028754 * A028756 A028757 A028758

Keyword

nonn,fini,full,easy

Author

N. J. A. Sloane

Extensions

Incorrect term 21 removed by Alonso del Arte, Dec 01 2019

Status

approved