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Pseudoprimes to base 5, written in base 5.
7

%I #26 Jul 25 2021 02:40:11

%S 4,444,1332,4221,11111,22131,23404,30031,42241,112443,133321,134421,

%T 140122,140411,202401,214244,222223,224104,241121,304011,323131,

%U 331401,402201,404041,411313,421411,434411,1001001,1001331,1010142,1032032,1140421,1212131,1224103,1233321,1302302,1302401,1414331,1421124,1440143

%N Pseudoprimes to base 5, written in base 5.

%H Amiram Eldar, <a href="/A262102/b262102.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A007091(A005936(n)).

%t base = 5; t = {}; n = 1;

%t While[Length[t] < 40, n++;

%t If[! PrimeQ[n] && PowerMod[base, n - 1, n] == 1,

%t AppendTo[t, FromDigits@IntegerDigits[n, 5]]]]; t

%o (PARI) lista(nn, b=5) = {for (n=1, nn, if (Mod(b, n)^(n-1)==1 && !ispseudoprime(n) && n>1, print1(subst(Pol(digits(n,b), x), x, 10), ", ");););} \\ _Michel Marcus_, Sep 30 2015

%Y Cf. A007091 (numbers in base 5), A005936 (pseudoprimes to base 5).

%Y Cf. A258189, A262101, A262103, A262104, A262105, A262154.

%K nonn,base

%O 1,1

%A _Abdul Gaffar Khan_, Sep 11 2015