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%I #17 May 23 2021 02:50:53
%S 2,3,11,5,13,7,11,29,19,11,19,13,29,23,19,17,23,19,31,29,29,23,29,37,
%T 37,29,31,29,43,31,37,37,59,59,43,37,41,59,43,41,59,43,47,47,53,47,59,
%U 61,59,61,59,53,67,59,59,59,61,59,73,61,71,67,79,71,89,67,71,101,89
%N Smallest prime whose base-n reversal is not a prime.
%C All primes show up in the sequence eventually.
%H Amiram Eldar, <a href="/A075240/b075240.txt">Table of n, a(n) for n = 2..10000</a>
%e 11_10 = 23_4, reverse(23) = 32, 32_4 = 14_10, so a(4) = 11 since this does not work for smaller primes.
%t a = {}; Do[k = 1; While[ PrimeQ[ FromDigits[ Reverse[ IntegerDigits[ Prime[k], n]], n]], k++ ]; a = Append[a, Prime[k]], {n, 2, 70}]; a
%o (PARI) a(n) = my(p=2); while (isprime(fromdigits(Vecrev(digits(p, n)), n)), p = nextprime(p+1)); p; \\ _Michel Marcus_, Mar 28 2021
%Y Cf. A075241, A075242.
%K base,easy,nonn
%O 2,1
%A _Robert G. Wilson v_, Sep 09 2002
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