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 A364484 #18 Aug 29 2023 16:30:19 %S A364484 2,22,44,121,211,242,422,484,844,2048,2111,2221,2321,4096,4222,4442, %T A364484 4642,8444,8884,9284,12211,21121,21211,21221,22111,22528,23221,24422, %U A364484 24431,25531,42242,42422,42442,44222,44521,45056,46442,48844,48862,51062,84484,84844,84884,88444,89042,92884,97724 %N A364484 Numbers whose prime factorization (prime factors and exponents) contains the digits 1 and 2 at least once, but no other digits. %e A364484 9284 is a term because 9284 = 2^2 * 11^1 * 211^1. %o A364484 (PARI) for(n=1, 1e5, v=[]; s=Set(v); f=factor(n); k=#f[, 1]; for(i=1, k, s1=Set(digits(f[i, 1])); s=setunion(s, s1)); for(i=1, k, s2=Set(digits(f[i, 2])); s=setunion(s, s2)); if(s==[1, 2], print1(n, ", "))) %Y A364484 Cf. A007931. %K A364484 nonn,base %O A364484 1,1 %A A364484 _Alexandru Petrescu_, Jul 26 2023