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%I A340795 #51 Feb 23 2021 12:22:09
%S A340795 0,0,0,0,0,0,1,1,0,1,0,1,1,2,1,2,0,1,0,2,2,1,0,3,0,2,1,3,0,3,1,3,1,1,
%T A340795 2,3,0,1,2,4,0,4,1,2,2,1,0,5,1,2,1,3,0,3,1,5,1,1,0,6,0,2,3,4,2,3,0,2,
%U A340795 1,5,0,6,1,1,2,2,2,4,0,6,2,1,0,7,1,2,1,4,0,6
%N A340795 a(n) is the number of divisors of n that are Brazilian.
%C A340795 The cases a(n) = 0 and a(n) = 1 are respectively detailed in A341057 and A341058.
%H A340795 David A. Corneth, <a href="/A340795/b340795.txt">Table of n, a(n) for n = 1..10000</a>
%H A340795 Wikipédia, <a href="https://fr.wikipedia.org/wiki/Nombre_br%C3%A9silien">Nombre brésilien</a> (in French).
%H A340795 <a href="/index/Br#Brazilian_numbers">Index entries for sequences related to Brazilian numbers</a>.
%e A340795 For n = 16, the divisors are 1, 2, 4, 8 and 16. Only 8 = 22_3 and 16 = 22_7 are Brazilian numbers, so a(16) = 2.
%e A340795 For n = 30, the divisors are 1, 2, 3, 5, 6, 10, 15 and 30. Only 10 = 22_4, 15 = 33_4 and 30 = 33_9 are Brazilian numbers, so a(30) = 3.
%e A340795 For n = 49, the divisors are 1, 7 and 49. Only 7 = 111_2 is Brazilian, so a(49) = 1 although 49 that is square of prime <> 121 is not Brazilian.
%t A340795 brazQ[n_] := Module[{b = 2, found = False}, While[b < n - 1 && Length[Union[IntegerDigits[n, b]]] > 1, b++]; b < n - 1]; a[n_] := DivisorSum[n, 1 &, brazQ[#] &]; Array[a, 100] (* _Amiram Eldar_, Jan 21 2021 *)
%o A340795 (PARI) isb(n) = for(b=2, n-2, d=digits(n, b); if(vecmin(d)==vecmax(d), return(1))); \\ A125134
%o A340795 a(n) = sumdiv(n, d, isb(d)); \\ _Michel Marcus_, Jan 24 2021
%Y A340795 Cf. A085104, A125134, A220627, A308851, A340796, A340797, A341057, A341058.
%K A340795 nonn,base
%O A340795 1,14
%A A340795 _Bernard Schott_, Jan 21 2021

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