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 A118915 #12 Sep 14 2024 06:47:16 %S A118915 5,13,19,23,37,41,89,113,127,131,139,149,167,197,229,233,239,251,271, %T A118915 359,373,401,433,449,463,503,523,541,607,631,643,653,701,719,743,769, %U A118915 811,827,877,881,887,919,967,971,1009,1013,1021,1093,1097,1283,1301 %N A118915 Primes p such that (p^2 + 5)/6 is prime. %C A118915 For all primes q>3, we have q=6k+-1 for some k, which makes it easy to show that 6 divides q^2+5. %C A118915 (n^2+5)/6 is an integer for all primes except 2 and 3. - _Michael B. Porter_, Apr 14 2010 %t A118915 Select[Prime[Range[215]],PrimeQ[(#^2+5)/6]&] (* _James C. McMahon_, Sep 13 2024 *) %o A118915 (PARI) isA118915(n)=if(n^2%6==1,isprime(n)&&isprime((n^2+5)/6),0) \\ _Michael B. Porter_, Apr 14 2010 %Y A118915 Cf. A109953 (primes p such that (p^2+1)/3 is prime), A118918 (primes p such that (p^2+11)/12 is prime). %K A118915 nonn %O A118915 1,1 %A A118915 _T. D. Noe_, May 05 2006