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 A144724 #14 Jul 24 2023 10:57:53
%S A144724 1,3,5,7,8,9,11,12,14,17,20,24,30,34,44,72,85,86,92,115,122,125,132,
%T A144724 142,150,161,162,181,186,198,224,248,252,282,283,290,307,319,321,344,
%U A144724 350,376,445,476,567,623,676,682,704,741,749,786,803,806,893,1014,1046,1079
%N A144724 a(n) is the smallest positive integer such that b * (Product_{k=1..n} a(k)) + 1 is prime, with b = 4.
%C A144724 Is this A144717 without the 2? - _R. J. Mathar_, Jul 24 2023
%e A144724 4*1+1=5 is prime => a(1)=1.
%e A144724 4*1*2+1=9 is not prime (omitted).
%e A144724 4*1*3+1=13 is prime => a(2)=3.
%t A144724 k = 4; a = {}; Do[If[PrimeQ[k n + 1], k = k n; AppendTo[a, n]], {n, 1, 3000}]; a (* Artur Jasinski *)
%Y A144724 Cf. A046966, A046972, A144717, A144718, A144722, A144723, A144725, A144726, A144727, A144728, A144729, A144730, A144731.
%K A144724 nonn
%O A144724 1,2
%A A144724 _Artur Jasinski_, Sep 19 2008
%E A144724 Definition corrected by _Georg Fischer_, Jun 18 2021