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 A217422 #22 May 13 2017 00:08:15 %S A217422 981750581622330147995648,28801196957834700781586432, %T A217422 835992910761480393266512789504,7295132596707416278470844481536, %U A217422 76976152675689985407324172386304 %N A217422 Numbers of the form 2^r*17^s whose decimal representations are such that each digit 0-9 appears a prime number of times. %C A217422 See formula section for more data. Others in cross-reference are similar and some hold more motivation in comments. %F A217422 A217422(n) = 2^A217423(n)*17^A217424(n). %e A217422 A217423(1)=47 and A217424(1)=8, so this sequence's first term is 2^47 * 17^8. It has in its decimal representation two copies each of the digits 0, 2, 3, 4, 6 and 7; and three copies each of 1, 5, 8 and 9. %Y A217422 Cf. A217854, A217423, A217424, A217404, A217407, A217410, A217413, A217416, A217419, A217425, A217428, A217431. %K A217422 nonn,base,less %O A217422 1,1 %A A217422 _James G. Merickel_, Oct 05 2012