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 A382199 #7 Mar 18 2025 13:47:16 %S A382199 3,11,131,173,491,797,947,1931,3583,4391,6173,7937,32323,49919,64499, %T A382199 79997,83383,149111,232333,296269,366161,477947,611333,616169,616961, %U A382199 635563,667673,969179,1111991,1779779,2232523,2662669,2922229,3444341,5333353,5599999,6853663,6919691,6929929 %N A382199 Primes p such that for each digit of p, 2*p*(digit) + 1 is prime. %o A382199 (PARI) isok(k) = if (isprime(k), my(d=Set(digits(k))); for (i=1, #d, if (!isprime(2*k*d[i]+1), return(0))); return(1)); \\ _Michel Marcus_, Mar 18 2025 %Y A382199 Subsequence of primes of A382179. %Y A382199 Cf. A382127, A382198. %K A382199 nonn,base %O A382199 1,1 %A A382199 _Michel Marcus_, Mar 18 2025