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 A129475 #10 Mar 27 2024 08:05:05
%S A129475 23869461181,39279010921,45608421601,58345550881,64788537493,
%T A129475 79681330633,83807064853,86315197987,91658731403,97331927117,
%U A129475 102581556673,104758832257,106426256653,111136152961,111795382441,125586978001,143216767091,144155203267,144708098881
%N A129475 Primes of Erdos-Selfridge class 15+.
%C A129475 a(1..19) calculated using A129474 up to 75e9, which gives A129475(20) > 150e9. This is enough to ensure that 288310406533 = A005113(16).
%H A129475 <a href="/index/Pri#primes_Erdos_Selfridge">Index entries for sequences related to the Erdos-Selfridge classification</a>
%F A129475 { a(n) } = { p = 2*m*A129474(k)-1 | k=1,2,3... and m=1,2,3... such that p is prime and m has no factor of class > 14+ }
%e A129475 23869461181 = 1+2*7*1704961513, where 1704961513 is in A129474
%o A129475 (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 A129475 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 A129475 A129475=nextclass(A129474)
%K A129475 nonn
%O A129475 1,1
%A A129475 _M. F. Hasler_, Apr 16 2007
%E A129475 Extended to a(19) by _M. F. Hasler_, Jan 12 2014