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 A116947 #15 Aug 05 2025 18:05:26 %S A116947 1,2,3,5,7,17,20,22,28,30,40,45,67,68,70,75,82,85,87,88,95,108,123, %T A116947 125,140,150,153,163,172,190,197,200,210,217,220,223,232,237,248,268, %U A116947 270,282,283,287,303,310,320,333,340,358,367,403,405,407,423,438,445,447 %N A116947 Numbers k such that 4*k^6 + 1 is prime. %e A116947 If k=197 then (4*k^6 + 1) is a prime with 15 digits. %t A116947 Select[Range[500], PrimeQ[(4*#^6 + 1)] &] (* _Stefan Steinerberger_, Apr 06 2006 *) %o A116947 (PARI) is(n)=isprime(4*n^6+1) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A116947 Cf. A115104, A001912, A115349. %K A116947 nonn,less,easy %O A116947 1,2 %A A116947 _Parthasarathy Nambi_, Apr 03 2006 %E A116947 More terms from _Stefan Steinerberger_, Apr 06 2006