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 A228271 #8 Apr 03 2023 10:36:13 %S A228271 473267,1919128,2131583,2390652,2844914,2982584,3909324,4280455, %T A228271 4658285,4728653,5165402,5254365,5369468,5458298,5551421,5647232, %U A228271 5817553,6070101,6334188,6495802,6877047,7027013,7074295,7087303,7157062,7369010,7392411,7946633,8469597 %N A228271 Prime-free centuries such that the next century is also prime-free. %H A228271 G. L. Honaker, Jr. and Chris Caldwell, <a href="https://t5k.org/curios/cpage/8999.html">Prime Curios! 473268</a> %e A228271 473267 is in the sequence because there is no prime between 47326699 and 47326900. %o A228271 (PARI) d=100; for(n=1, 10^7, if(nextprime(d*n)>d*(n+2), print1(n, ", "))); %Y A228271 Cf. A181098, A190639. %K A228271 nonn,base %O A228271 1,1 %A A228271 _Arkadiusz Wesolowski_, Aug 19 2013