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 A036317 #23 May 22 2022 05:51:18 %S A036317 9,27,81,243,249,729,747,1149,2187,2241,2649,3447,6561,6723,6889,7947, %T A036317 10341,11499,19683,20169,20667,23841,31023,31789,34497,59049,60507, %U A036317 62001,71523,73289,93069,95367,103491,114999,116499,146689,177147 %N A036317 Composite numbers whose prime factors contain no digits other than 3 and 8. %C A036317 All terms are a product of at least two terms of A020464. - _David A. Corneth_, Oct 09 2020 %H A036317 David A. Corneth, <a href="/A036317/b036317.txt">Table of n, a(n) for n = 1..10000</a> %H A036317 <a href="/index/Pri#prime_factors">Index entries for sequences related to prime factors</a>. %F A036317 Sum_{n>=1} 1/a(n) = Product_{p in A020464} (p/(p - 1)) - Sum_{p in A020464} 1/p - 1 = 0.1750565813... . - _Amiram Eldar_, May 22 2022 %Y A036317 Cf. A020464, A036302-A036325. %K A036317 nonn,easy,base %O A036317 1,1 %A A036317 _Patrick De Geest_, Dec 15 1998