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 A216666 #28 Feb 20 2023 03:17:48 %S A216666 1,1,1,1,6524,809652228,30717523794,55779743835 %N A216666 Smallest integer b such that (b+1)^p - b^p is prime for all primes p <= prime(n). %C A216666 Is this sequence infinite? %C A216666 a(9) > 10^11. - _Tyler Busby_, Feb 20 2023 %e A216666 a(1)=a(2)=a(3)=a(4)=1 since 2^2-1, 2^3-1, 2^5-1 and 2^7-1 are primes. %Y A216666 Cf. A216668. %K A216666 nonn,hard,more %O A216666 1,5 %A A216666 _Jean-Louis Charton_, Sep 13 2012 %E A216666 a(7) from _Jean-Louis Charton_, Sep 18 2012 %E A216666 a(8) from _Jean-Louis Charton_, Oct 02 2012