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 A052080 #22 Mar 04 2021 04:39:43 %S A052080 2,4,0,10,7,0,73,46,0,56,219,0,25,60,0,52,117,0,535,172,0 %N A052080 Concatenation of n consecutive descending numbers starting from a(n) produces the smallest possible prime of this form, 0 if no such prime exists. %C A052080 First hard cases occur for n = 22, 88 and 110. %C A052080 a(22) = 10^1631 + 10 was found by _James G. Merickel_ in Feb 2011. %C A052080 a(88) = 10^14 + 6. %C A052080 a(110) = 10^19 + 26 was found by Chris Nash. %H A052080 C. Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_078.htm">Prime Puzzle 78</a> %e A052080 For n = 8 we have a(8) = 46 so the eight consecutive descending numbers 46,45,44,43,42,41,40 and 39 concatenated together gives the smallest possible prime of this form, 4645444342414039. %Y A052080 Cf. A052077, A052078, A052079. %K A052080 nonn,base,hard %O A052080 1,1 %A A052080 _Patrick De Geest_, Jan 15 2000 %E A052080 Terms a(7)-a(21) calculated by _Carlos Rivera_ and _Felice Russo_