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 A217416 #20 May 09 2021 02:23:38 %S A217416 19461082905477938625332224,1493825030770756769826391724130304, %T A217416 1341437769548771819714842333610521088, %U A217416 1888426137230419620556768936800026624 %N A217416 Numbers of the form 2^r*13^s whose decimal representations are such that each digit 0-9 appears a prime number of times. %C A217416 See the formula section for more data, and the other sequences in cross-reference for similar and motivation. %F A217416 a(n) = 2^A217417(n) * 13^A217418(n). %e A217416 A217417(1)=10 and A217418(1)=20, so this sequence's first term can be simply written as 338^10 (338=2*13^2). It has two each of 0's, 1's, 5's, 6's, 7's and 8's; three each of 3's, 4's and 9's; and five 2's. %Y A217416 Cf. A217854, A217417, A217418, A217404, A217407, A217410, A217413, A217419, A217422, A217425, A217428, A217431. %K A217416 nonn,base,less %O A217416 1,1 %A A217416 _James G. Merickel_, Oct 03 2012