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 A268067 #22 Nov 04 2024 01:44:18 %S A268067 1,17,1295,63445 %N A268067 Numbers k such that 1 + 2^k + 3^k + 5^k is prime. %C A268067 a(4), if it exists, is greater than 50000. - _Michael S. Branicky_, Mar 31 2023 %t A268067 Select[Range[0, 2000], PrimeQ[1 + 2^# + 3^# + 5^#] &] %o A268067 (PARI) lista(nn) = for(n=0, nn, if(ispseudoprime(1 + 2^n + 3^n + 5^n), print1(n, ", "))); \\ _Altug Alkan_, Jan 25 2016 %Y A268067 Cf. A076515, A268064, A268065. %K A268067 nonn,more %O A268067 1,2 %A A268067 _Vaclav Kotesovec_, Jan 25 2016 %E A268067 a(4) from _Michael S. Branicky_, Nov 03 2024