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 A066266 #38 Feb 16 2025 08:32:45
%S A066266 3,13,361,75601,174636001,5244319080001,2677277333530800001,
%T A066266 25968760179275365452000001,5793445238736255798985527240000001,
%U A066266 37481813439427687898244906452608585200000001,7517370874372838151564668004911177464757864076000000001
%N A066266 Product of first n primorials + 1.
%H A066266 Harry J. Smith, <a href="/A066266/b066266.txt">Table of n, a(n) for n = 1..37</a>
%H A066266 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 A066266 Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_118.htm">Puzzle 118. Primorial product numbers</a>, The Prime Puzzles & Problems Connection.
%H A066266 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Primorial.html">Primorial.</a>
%F A066266 a(n) = A006939(n) + 1. - _Andrew Howroyd_, Dec 10 2024
%e A066266 a(3)=361 since 361 = (2)*(2*3)*(2*3*5) + 1.
%t A066266 Table[Times@@Table[Times@@Prime[Range[n]],{n,k}]+1,{k,40}] (* _Jayanta Basu_, May 12 2013 *)
%t A066266 Rest[FoldList[Times,1,Rest[FoldList[Times,1,Prime[Range[10]]]]]]+1 (* _Harvey P. Dale_, Sep 16 2013 *)
%o A066266 (PARI) a(n) = 1 + prod(k=1, n, prime(k)^(n-k+1)) \\ _Andrew Howroyd_, Dec 10 2024
%Y A066266 Cf. A066267, A066268, A066269, A002110, A006939, A005234.
%K A066266 nonn
%O A066266 1,1
%A A066266 _Patrick De Geest_, Dec 16 2001
%E A066266 Offset changed from 0 to 1 by _Harry J. Smith_, Feb 08 2010