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A028769 Nonsquares mod 56. 1
2, 3, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 29, 30, 31, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..44.

MATHEMATICA

Complement[Range[0, 55], PowerMod[Range[56], 2, 56]] (* Alonso del Arte, Dec 28 2019 *)

PROG

(PARI) is(n)=!issquare(Mod(n, 56)) && n>0 && n<56 \\ Charles R Greathouse IV, Apr 27 2015

(Scala) (0 to 55).diff((1 to 56).map(n => (n * n) % 56)) // Alonso del Arte, Dec 28 2019

CROSSREFS

Cf. A010417.

Sequence in context: A259444 A071591 A089105 * A094784 A085971 A175082

Adjacent sequences:  A028766 A028767 A028768 * A028770 A028771 A028772

KEYWORD

nonn,fini,full,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified May 6 21:35 EDT 2021. Contains 343597 sequences. (Running on oeis4.)