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 A339347 #17 Dec 15 2020 17:35:06 %S A339347 5,7,11,13,19,31,37,43,61,67,71,73,79,101,131,151,191,197,211,239,251, %T A339347 281,311,331,401,419,421,431,443,461,463,491,521,547,571,599,601,617, %U A339347 647,659,677,683,727,743,827,859,883,911,947,953,967,1013,1093,1103 %N A339347 Primes p such that p < (gpf((p - 1)/gpf(p - 1)))^4, where gpf(k) is the greatest prime factor of k, A006530. %C A339347 Inspired by A339466. See the references there. %H A339347 Robert Israel, <a href="/A339347/b339347.txt">Table of n, a(n) for n = 1..10000</a> %p A339347 alias(pf = NumberTheory:-PrimeFactors): gpf := n -> max(pf(n)): %p A339347 is_a := n -> isprime(n) and n < (gpf((n-1)/gpf(n-1)))^4: %p A339347 select(is_a, [$5..1150]); %o A339347 (PARI) gpf(n) = if (n==1, 1, vecmax(factor(n)[, 1])); \\ A006530 %o A339347 isok(p) = isprime(p) && (p < (gpf((p - 1)/gpf(p - 1)))^4); \\ _Michel Marcus_, Dec 14 2020 %Y A339347 Cf. A006530, A339466. %K A339347 nonn %O A339347 1,1 %A A339347 _Peter Luschny_, Dec 13 2020