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 A306747 #9 Mar 08 2019 16:05:17 %S A306747 2,5,2642,546046 %N A306747 Untouchable numbers with a record gap to the next untouchable number. %C A306747 The record gap values are 3, 47, 62, 74. %C A306747 Guy asks "How large can the gaps between untouchable numbers be?" %D A306747 Richard K. Guy, Unsolved Problems in Number Theory, 3rd Edition, Springer, 2004, Section B10, p. 101. %H A306747 Giovanni Resta, <a href="http://www.numbersaplenty.com/set/untouchable_number/">Untouchable numbers</a> (terms up to 10^6) %e A306747 5 is in the sequence since it is an untouchable number and the next untouchable number after it is 52 = 5 + 47 with a record gap of 47. The next gap which is larger than 47 occurs at 2642 which is followed by 2704 = 2642 + 62. %Y A306747 Cf. A005114, A231965. %K A306747 nonn,hard,more %O A306747 1,1 %A A306747 _Amiram Eldar_, Mar 07 2019