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A136803 Squares mod 257. 4
0, 1, 2, 4, 8, 9, 11, 13, 15, 16, 17, 18, 21, 22, 23, 25, 26, 29, 30, 31, 32, 34, 35, 36, 42, 44, 46, 49, 50, 52, 57, 58, 59, 60, 61, 62, 64, 67, 68, 70, 72, 73, 79, 81, 84, 88, 89, 92, 95, 98, 99, 100, 104, 111, 113, 114, 116, 117, 118, 120, 121, 122, 123, 124 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Because 257 is a Fermat prime, the complement of this set, A136804, is the set of primitive roots (mod 257).

LINKS

Nathaniel Johnston, Table of n, a(n) for n = 1..129 (full sequence)

OEIS Wiki, Index to sequences related to squares

FORMULA

a(n) + a(131-n) = 257 for n>1.

MAPLE

A136803 := {}: for n from 0 to 256 do A136803 := A136803 union {n^2 mod 257}: od: op(sort(convert(A136803, list))); # Nathaniel Johnston, Jun 23 2011

MATHEMATICA

p = 257; Select[Range[0, p - 1], JacobiSymbol[ #, p] == 1 &] (* T. D. Noe *)

Table[Mod[n^2, 257], {n, 0, 65}] (* Alonso del Arte, Feb 14 2013 *)

PROG

(PARI) for (n=0, 256, if (issquare(Mod(n, 257)), print1(n, ", "))) \\ Michel Marcus, Mar 12 2017

(PARI) A136803=Set([k^2 | k <- [0..256]]%257); \\ M. F. Hasler, Nov 15 2017

(PARI) lift(select(issquare, Mod([0..256], 257))) \\ M. F. Hasler, Nov 15 2017

CROSSREFS

Cf. A136804 (nonsquares mod 257), A136805 and A136806 (squares/nonsquares mod 65537).

Sequence in context: A325942 A325944 A165569 * A035268 A035241 A034036

Adjacent sequences:  A136800 A136801 A136802 * A136804 A136805 A136806

KEYWORD

fini,full,easy,nonn

AUTHOR

T. D. Noe, Jan 22 2008

STATUS

approved

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Last modified October 19 08:46 EDT 2021. Contains 348074 sequences. (Running on oeis4.)