This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A091923 #17 Sep 08 2022 08:45:13 %S A091923 11,13,17,19,23,31,37,41,47,53,59,71,73,79,83,97,101,103,107,109,113, %T A091923 127,131,137,149,151,157,163,167,173,179,181,191,211,223,229,233,239, %U A091923 241,251,257,271,277,283,293,307,311,313,317,337,347,349,359,367,383 %N A091923 Primes whose decimal representations interpreted in base 11 are not prime. %C A091923 A090862(A049084(a(n))) = 11. %H A091923 Marius A. Burtea, <a href="/A091923/b091923.txt">Table of n, a(n) for n = 1..1045</a> %e A091923 A000040(9)=23 in base 11 is 2*11^1 + 3*11^0 = 25 = 5^2, therefore 29 is a term. %t A091923 Select[Prime@Range@80, ! PrimeQ@FromDigits[IntegerDigits@#, 11] &] (* _Vincenzo Librandi_, Jul 01 2019 *) %o A091923 (Magma) [n:n in PrimesUpTo(400)| not IsPrime(Seqint(Intseq(n), 11))]; // _Marius A. Burtea_, Jun 30 2019 %o A091923 (PARI) isok(p) = isprime(p) && (d=digits(p)) && !isprime(fromdigits(d, 11)); \\ _Michel Marcus_, Jun 30 2019 %Y A091923 Cf. A091924. %K A091923 nonn,base %O A091923 1,1 %A A091923 _Reinhard Zumkeller_, Feb 13 2004 %E A091923 Corrected by _Zak Seidov_, Feb 25 2004