%I #23 May 22 2022 05:51:18

%S 9,27,81,243,249,729,747,1149,2187,2241,2649,3447,6561,6723,6889,7947,

%T 10341,11499,19683,20169,20667,23841,31023,31789,34497,59049,60507,

%U 62001,71523,73289,93069,95367,103491,114999,116499,146689,177147

%N Composite numbers whose prime factors contain no digits other than 3 and 8.

%C All terms are a product of at least two terms of A020464. - _David A. Corneth_, Oct 09 2020

%H David A. Corneth, <a href="/A036317/b036317.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Pri#prime_factors">Index entries for sequences related to prime factors</a>.

%F 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 Cf. A020464, A036302-A036325.

%K nonn,easy,base

%O 1,1

%A _Patrick De Geest_, Dec 15 1998