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A258165 Odd non-Brazilian numbers > 1.

%I A258165 #42 May 09 2021 05:09:08
%S A258165 3,5,9,11,17,19,23,25,29,37,41,47,49,53,59,61,67,71,79,83,89,97,101,
%T A258165 103,107,109,113,131,137,139,149,151,163,167,169,173,179,181,191,193,
%U A258165 197,199,223,227,229,233,239,251,257,263,269,271,277,281,283,289,293,311,313,317,331,337
%N A258165 Odd non-Brazilian numbers > 1.
%C A258165 Complement of A257521 in A144396 (odd numbers > 1).
%C A258165 The terms are only odd primes or squares of odd primes.
%C A258165 Most odd primes are present except those in A085104.
%C A258165 All terms which are not primes are squares of odd primes except 121 = 11^2.
%H A258165 Vincenzo Librandi, <a href="/A258165/b258165.txt">Table of n, a(n) for n = 1..1150</a>
%e A258165 11 is present because there is no base b < 11 - 1 = 10 such that the representation of 11 in base b is a repdigit (all digits are equal). In fact, we have: 11 = 1011_2 = 102_3 = 23_4 = 21_5 = 15_6 = 14_7 = 13_8 = 12_9, and none of these representations are repdigits. - _Bernard Schott_, Jun 21 2017
%t A258165 fQ[n_] := Block[{b = 2}, While[b < n - 1 && Length@ Union@ IntegerDigits[n, b] > 1, b++]; b+1 == n]; Select[1 + 2 Range@ 170, fQ]
%o A258165 (PARI) forstep(n=3, 300, 2, c=1; for(b=2, n-2, d=digits(n, b); if(vecmin(d)==vecmax(d), c=0;  break));if(c,print1(n,", "))) \\ _Derek Orr_, May 27 2015
%o A258165 (Python)
%o A258165 from sympy.ntheory.factor_ import digits
%o A258165 l=[]
%o A258165 for n in range(3, 301, 2):
%o A258165     c=1
%o A258165     for b in range(2, n - 1):
%o A258165         d=digits(n, b)[1:]
%o A258165         if max(d)==min(d):
%o A258165             c=0
%o A258165             break
%o A258165     if c: l.append(n)
%o A258165 print(l) # _Indranil Ghosh_, Jun 22 2017, after PARI program
%Y A258165 Cf. A085104, A125134, A190300, A220570, A220571, A220627, A242397, A253260, A253261, A257521.
%K A258165 nonn
%O A258165 1,1
%A A258165 _Daniel Lignon_ and _Robert G. Wilson v_, May 22 2015