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A325323 Palindromes in base 10 that are not Brazilian. 2

%I #33 Apr 14 2021 05:25:13

%S 1,2,3,4,5,6,9,11,101,131,151,181,191,313,353,373,383,727,787,797,919,

%T 929,10201,10301,10501,10601,11311,11411,12421,12721,12821,13331,

%U 13831,13931,14341,14741,15451,15551,16061,16361,16561,16661,17471,17971,18181,18481,19391,19891,19991

%N Palindromes in base 10 that are not Brazilian.

%C The terms >= 11 of this sequence are either prime palindromes which are not Brazilian, or square of primes (except 121).

%H Amiram Eldar, <a href="/A325323/b325323.txt">Table of n, a(n) for n = 1..1000</a>

%t brazQ[n_] := Module[{b = 2, found = False}, While[b < n - 1 && Length @ Union[IntegerDigits[n, b]] > 1, b++]; b < n - 1]; Select[Range[20000], PalindromeQ[#] && !brazQ[#] &] (* _Amiram Eldar_, Apr 14 2021 *)

%o (PARI) isb(n) = for(b=2, n-2, my(d=digits(n, b)); if(vecmin(d)==vecmax(d), return(1))); \\ A125134

%o isp(n) = my(d=digits(n)); d == Vecrev(d); \\ A002113

%o isok(n) = !isb(n) && isp(n); \\ _Michel Marcus_, Apr 22 2019

%Y Intersection of A002113 and A220570.

%Y Complement of A325322 with respect to A002113.

%Y Cf. A088882 (Palindromes not repdigits).

%K nonn,base

%O 1,2

%A _Bernard Schott_, Apr 20 2019

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Last modified July 1 11:07 EDT 2024. Contains 373915 sequences. (Running on oeis4.)