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 A068489 #28 Jan 15 2024 10:03:13
%S A068489 3,10,5,343,3248,18,16,12,22,20324,50,9414916809095,13120,43,8481,
%T A068489 1200361259,196,38,10326732314,65,38,34
%N A068489 m for which prime(m) is the least prime dividing #prime(n) - 1, i.e., one less than primorial n-th prime (A057588).
%C A068489 Since #P13 - 1 is a prime, see A006794, we need the number of primes less than or equal to #P13 - 1. The sequence continues, for n=14 to 23: 13120, 43, 8481, 1200361259, 196, 38, 10326732314, 65, 38, 34.
%C A068489 a(24) = pi(23768741896345550770650537601358309). - _Donovan Johnson_, Dec 08 2009
%H A068489 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 A068489 Hisanori Mishima, <a href="http://www.asahi-net.or.jp/~KC2H-MSM/mathland/matha1/matha103.htm">Factorization results #Pn (Primorial) - 1</a>.
%F A068489 a(n) = A000720(A057713(n)).
%t A068489 Do[ Print[ PrimePi[ FactorInteger[ Product[ Prime[k], {k, 1, n}] - 1] [[1, 1]]]], {n, 2, 22} ]
%Y A068489 Cf. A000720, A006794, A057588, A057713, A068488.
%K A068489 hard,more,nonn
%O A068489 2,1
%A A068489 _Lekraj Beedassy_, Mar 11 2002
%E A068489 Edited and extended by _Robert G. Wilson v_, Mar 12 2002
%E A068489 a(13) from _Donovan Johnson_, Dec 08 2009