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 A155048 #16 Feb 19 2021 02:54:48 %S A155048 7,11,17,19,23,191,199,211,227,251,277,281,311,337,347,353,359,373, %T A155048 383,389,397,401,409,419,439,463,467,479,523,547,557,569,571,577,593, %U A155048 599,613,619,641,643,653,659,673,677,683,701,709,743,751,757,769,787,809 %N A155048 Primes p such that number of prime digits of prime(p) = number of nonprime digits of prime(p). %C A155048 Prime digits are 2, 3, 5 or 7, nonprime digit are 0, 1, 4, 6, 8 or 9. %o A155048 (PARI) f(n) = #select(isprime, digits(prime(n))); \\ A109066 %o A155048 isok(p) = my(nbp=f(prime(p))); isprime(p) && (2*f(p) == #digits(prime(p))); \\ _Michel Marcus_, Feb 18 2021 %Y A155048 Cf. A000040, A109066, A141468. %K A155048 nonn,base,less %O A155048 1,1 %A A155048 _Juri-Stepan Gerasimov_, Jan 19 2009 %E A155048 Corrected (17 and 479 inserted) by _R. J. Mathar_, May 05 2010