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Pseudoprimes to base 8, written in base 8.
7

%I #16 Jul 25 2021 02:40:33

%S 11,25,55,77,101,151,165,205,231,347,421,525,741,777,1061,1111,1205,

%T 1213,1535,1665,1751,2121,2401,2525,2553,2611,3005,3161,3175,3301,

%U 3371,3561,3777,4171,4641,4705,5215,5405,6111,6143

%N Pseudoprimes to base 8, written in base 8.

%H Amiram Eldar, <a href="/A262105/b262105.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A007094(A020137(n)).

%t base = 8; t = {}; n = 1;

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

%t If[! PrimeQ[n] && PowerMod[base, n - 1, n] == 1, AppendTo[t, FromDigits@ IntegerDigits[n, 8]]]]; t

%Y Cf. A007094 (Numbers in base 8), A020137 (Pseudoprimes to base 8).

%Y Cf. A258189, A262101, A262102, A262103, A262104, A262154.

%K nonn,base

%O 1,1

%A _Abdul Gaffar Khan_, Sep 11 2015