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Pseudoprimes to base 3, written in base 3.
7

%I #57 Jul 25 2021 02:39:58

%S 10101,11111,101121,220212,222001,1022011,1111221,2010002,2101001,

%T 2121001,10101022,10122201,10201001,10212111,11111112,11121201,

%U 12010221,20210202,21121121,100001111,101010101,102112011,110020001,112112001,120002211,122000101,201201201,202212002

%N Pseudoprimes to base 3, written in base 3.

%H Amiram Eldar, <a href="/A258189/b258189.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A007089(A005935(n)). - _Michel Marcus_, Sep 11 2015

%t base = 3; 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, 3]]]]; t

%o (PARI) lista(nn, b=3) = {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. A005935 (pseudoprimes to base 3), A007089 (numbers in base 3).

%Y Cf. A262101, A262102, A262103, A262104, A262105, A262154.

%K nonn,base

%O 1,1

%A _Abdul Gaffar Khan_, Sep 11 2015

%E a(25) corrected by _Georg Fischer_, Dec 18 2020