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 A129249 #10 Mar 27 2024 08:04:03
%S A129249 1432349099,1749565397,2771868719,3790874279,5288908679,5804138567,
%T A129249 6273146879,8123301983,8594094589,11055501923,11809566403,11914176299,
%U A129249 12647401799,13432673083,13925010299,14208729979
%N A129249 Primes of Erdos-Selfridge class 15-.
%C A129249 The fastest way to calculate the complete list of class N primes up to P is to use the given formula (or PARI function nextclass()) with the list of class (N-1) primes up to P/2.
%H A129249 M. F. Hasler, <a href="/A129249/b129249.txt">Table of n, a(n) for n = 1..48</a>
%H A129249 <a href="/index/Pri#primes_Erdos_Selfridge">Index entries for sequences related to the Erdos-Selfridge classification</a>
%F A129249 { a(n) } = { p = 2*m*A129248(k)+1 | k=1,2,3... and m=1,2,3... such that p is prime and m has no factor of class > 14- }
%o A129249 (PARI) class(n, s=1) = { if(!isprime(n),0, if(!(n=factor(n+s)[,1]) || n[ #n]<=3,1, for(i=2,#n,n[1]=max(class(n[i],s)+1,n[1]));n[1]))}
%o A129249 nextclass(a,s=-1,p,n=[])={if(!p,p=nextprime(a[ #a]+1)); print("producing primes of class ",1+class(a[1],s),["+","-"][1+(s<0)]," up to 2*",p); for(i=1,#a,for(k=1,p/a[i],if(isprime(2*k*a[i]-s),n=concat(n,2*k*a[i]-s))));vecsort(n)}
%o A129249 A129249=nextclass(A129248)
%K A129249 nonn
%O A129249 1,1
%A A129249 _M. F. Hasler_, Apr 16 2007, Apr 21 2007