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 A066267 #31 Feb 16 2025 08:32:45
%S A066267 1,2,5,12,15,35
%N A066267 Numbers k such that A066266(k) is prime.
%C A066267 The next term, if it exists, is greater than 120. - _Dmitry Kamenetsky_, May 11 2009
%C A066267 The next term, if it exists, is greater than 400. - _Michael S. Branicky_, Aug 08 2024
%H A066267 Romeo Meštrović, <a href="http://arxiv.org/abs/1202.3670">Euclid's theorem on the infinitude of primes: a historical survey of its proofs (300 BC--2012) and another new proof</a>, arXiv preprint arXiv:1202.3670 [math.HO], 2012-2023. - From N. J. A. Sloane, Jun 13 2012
%H A066267 Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_118.htm">Puzzle 118. Primorial product numbers</a>, The Prime Puzzles & Problems Connection.
%H A066267 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Primorial.html">Primorial</a>.
%t A066267 t={}; Do[If[PrimeQ[Times@@Table[Times@@Prime[Range[n]],{n,k}]+1],AppendTo[t,k]],{k,35}]; t (* _Jayanta Basu_, May 12 2013 *)
%Y A066267 Cf. A066266, A066268, A066269, A002110, A006939, A005234.
%K A066267 nonn,hard,more
%O A066267 1,2
%A A066267 _Patrick De Geest_, Dec 16 2001
%E A066267 Offset changed from 0 to 1 by _Harry J. Smith_, Feb 08 2010
%E A066267 Name simplified by _Jon E. Schoenfield_, Oct 25 2019