A242860 - OEIS

A242860

a(n) is the least k >= 2 such that k is neither a square modulo n nor a primitive root (mod n), or 0 if no such value exists.

0, 2, 0, 2, 6, 2, 3, 2, 10, 2, 5, 6, 2, 2, 0, 2, 8, 2, 2, 2, 22, 2, 5, 2, 3, 2, 12, 2, 6, 2, 2, 6, 2, 2, 6, 2, 2, 2, 3, 2, 2, 2, 2, 10, 46, 2, 6, 2, 2, 2, 23, 2, 2, 2, 2, 2, 58, 2, 8, 6, 2, 2, 2, 2, 3, 2, 2, 2, 14, 2, 7, 2, 2, 2, 2, 2, 12, 2, 3, 3, 82, 2, 2, 2

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OFFSET

3,2

COMMENTS

a(A019434(n)) = 0 for n >= 1.

LINKS

Table of n, a(n) for n=3..86.

Eric Weisstein's World of Mathematics, Primitive Root

PROG

(Magma) lst:=[]; for n in [3..86] do v:=0; for r in [2..n-1] do if not IsSquare(ResidueClassRing(n)! r) and not IsPrimitive(r, n) then v:=r; break; end if; end for; lst:=Append(lst, v); end for; lst;

CROSSREFS

Cf. A028730, A136804, A136806.

Sequence in context: A344873 A306079 A373167 * A320239 A033727 A033757

Adjacent sequences: A242857 A242858 A242859 * A242861 A242862 A242863

KEYWORD

nonn

AUTHOR

Arkadiusz Wesolowski, May 24 2014

STATUS

approved