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 A140331 #20 Aug 24 2024 06:59:42 %S A140331 1,4,2,26,10,466,506,128,13342,5974,8410,6470 %N A140331 Smallest k such that 3^(3^n) - k is prime. %C A140331 This is to 3 as A058220 is to 2. %F A140331 a(n) = A064722(A055777(n)). - _Michel Marcus_, Jan 28 2015 %e A140331 a(4) = 10 because 3^(3^4) - 10 = 443426488243037769948249630619149892793 is prime. %o A140331 (PARI) a(n) = x = 3^(3^n); x - precprime(x); \\ _Michel Marcus_, Jan 28 2015 %Y A140331 Cf. A055777 (3^(3^n)), A058220. %K A140331 more,nonn %O A140331 0,2 %A A140331 _Jonathan Vos Post_, May 26 2008 %E A140331 a(5)-a(8) from _Cino Hilliard_, Jun 02 2008 %E A140331 a(9)-a(10) from _Donovan Johnson_, Sep 13 2008 %E A140331 a(0) prepended and a(11) from _Michael S. Branicky_, Aug 23 2024