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A143663 a(n) is the least prime such that the multiplicative order of 3 mod a(n) equals n, or a(n)=1 if such prime does not exist. 3
2, 1, 13, 5, 11, 7, 1093, 41, 757, 61, 23, 73, 797161, 547, 4561, 17, 1871, 19, 1597, 1181, 368089, 67, 47, 6481, 8951, 398581, 109, 29, 59, 31, 683, 21523361, 2413941289, 103, 71, 530713, 13097927, 2851, 313, 42521761, 83, 43, 431, 5501, 181, 23535794707 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If a(n) differs from 1, then a(n) is the minimal prime divisor of A064079(n).

LINKS

Robert G. Wilson v, Table of n, a(n) for n = 1..153

MAPLE

a:= proc(n) local f, p;

f:= numtheory:-factorset(3^n - 1);

for  p in f do

   if numtheory:-order(3, p) = n then return p fi

od:

1

end proc:

seq(a(n), n=1..100); # Robert Israel, Oct 13 2014

MATHEMATICA

p = 2; t = Table[0, {100}]; While[p < 100000001, a = MultiplicativeOrder[3, p]; If[0 < a < 101 && t[[a]] == 0, t[[a]] = p; Print[{a, p}]];  p = NextPrime@ p]; t (* Robert G. Wilson v, Oct 13 2014 *)

CROSSREFS

Cf. A002326 A064079.

Sequence in context: A074955 A245625 A292947 * A064079 A167584 A112226

Adjacent sequences:  A143660 A143661 A143662 * A143664 A143665 A143666

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, Aug 28 2008

EXTENSIONS

More terms from Robert G. Wilson v, Dec 11 2013

STATUS

approved

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Last modified May 10 05:10 EDT 2021. Contains 343748 sequences. (Running on oeis4.)