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A028773 Nonsquares mod 60. 1
2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 22, 23, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 41, 42, 43, 44, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..48.

EXAMPLE

x^2 = 20 mod 60 has no solutions, so 20 is in the sequence.

x^2 = 21 mod 60 has the following solutions: x = 9, x = 21, x = 39, x = 51. Hence 21 is not in the sequence.

MATHEMATICA

Complement[Range[59], PowerMod[Range[60], 2, 60]] (* Alonso del Arte, Jan 13 2017 *)

PROG

(Scala) (0 to 59).diff((1 to 60).map(n => n * n % 60)) // Alonso del Arte, Jan 03 2020

CROSSREFS

Cf. A010421.

Sequence in context: A039251 A283296 A028797 * A028813 A158276 A028793

Adjacent sequences:  A028770 A028771 A028772 * A028774 A028775 A028776

KEYWORD

nonn,fini,full,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified September 30 02:03 EDT 2020. Contains 337432 sequences. (Running on oeis4.)