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 A128002 #35 Mar 22 2024 18:37:55 %S A128002 7,17,31,5581,9973,54493,101111,535571 %N A128002 Numbers k such that (31^k - 1)/30 is prime. %C A128002 a(5) = 9973 was found by Richard Fischer in 2004. - _Alexander Adamchuk_, Feb 11 2007 %H A128002 H. Dubner, <a href="http://dx.doi.org/10.1090/S0025-5718-1993-1185243-9">Generalized repunit primes</a>, Math. Comp., 61 (1993), 927-930. %H A128002 R. Fischer, <a href="http://www.fermatquotient.com/PrimSerien/GenRepu.txt">Generalized repunit primes of the form (B^N-1)/(B-1)</a>. %H A128002 H. Lifchitz, <a href="http://www.primenumbers.net/Henri/us/MersFermus.htm">Mersenne and Fermat primes field</a>. %H A128002 <a href="/index/Pri#primepop">Index to primes in various ranges</a>, form ((k+1)^n-1)/k %t A128002 Select[Prime[Range[100]],PrimeQ[(31^#-1)/30]&] %o A128002 (PARI) is(n)=ispseudoprime((31^n-1)/30) \\ _Charles R Greathouse IV_, Feb 17 2017 %K A128002 hard,more,nonn %O A128002 1,1 %A A128002 _Alexander Adamchuk_, Feb 11 2007 %E A128002 More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008 %E A128002 a(7) = 101111 by _Robert Price_, Nov 26 2011 %E A128002 a(8) = 535571 from Alexander Zhirkov, added by _Paul Bourdelais_, Jan 28 2021 %E A128002 Missing term 54493 inserted at the suggestion of _Eric Chen_ by _Max Alekseyev_, Aug 26 2023