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A010462

Squares mod 30.

0, 1, 4, 6, 9, 10, 15, 16, 19, 21, 24, 25

OFFSET

1,3

COMMENTS

Range of A070452; a(k) + a(13-k) = 25, 1 <= k <= 12. - Reinhard Zumkeller, Apr 24 2009

LINKS

EXAMPLE

3^2 = 9, so 9 is in the sequence.

10^2 and 20^2 are both congruent to 10 mod 30, so 10 is in the sequence.

There are no solutions to x^2 = 11 mod 30, so 11 is not in the sequence.

MATHEMATICA

Union[PowerMod[Range[30], 2, 30]] (* Alonso del Arte, Jan 30 2018 *)

PROG

(SageMath) [quadratic_residues(30)] # Zerinvary Lajos, May 24 2009

(Scala) (1 to 30).map(n => n * n).map(_ % 30).toSet.toSeq.sorted // Alonso del Arte, Nov 30 2019

CROSSREFS

Row 30 of A096008.

KEYWORD

nonn,fini,full

AUTHOR

STATUS

approved

URL: https://oeis.org/A010462