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 A216418 #8 Sep 17 2012 11:21:39 %S A216418 3,23,61,331,2837,18169 %N A216418 Fortunate numbers with increasing multiplicity. %C A216418 a(n) appears in A005235 more often than any preceding term. %C A216418 Is this sequence infinite? %e A216418 3 is the first term of A005235, so a(1) = 3. A005235(5) = A005235(8) = 23, while smaller primes appear only once, so a(2) = 23. %o A216418 (PARI) ct(p)=my(pr=1,s);forprime(q=2,p-1,if(!ispseudoprime((pr*=q)+p), next);forprime(r=q+1,p-1,if(ispseudoprime(pr+r),next(2)));s++);s %o A216418 r=0;forprime(p=2,2e3,t=ct(p);if(t>r,r=t;print1(p", "))) %Y A216418 Cf. A005235, A046066. %K A216418 nonn,hard,more %O A216418 1,1 %A A216418 _Charles R Greathouse IV_, Sep 06 2012 %E A216418 a(6) from _Charles R Greathouse IV_, Sep 17 2012