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 A323084 #14 Jan 07 2019 04:32:23 %S A323084 0,1,12,21,4224,153426,442451,471614,523291,4336232,474335342, %T A323084 3624263478,36443455382,244936365228,452527642826,593326437534, %U A323084 4372566243537 %N A323084 k-digit numbers whose digit(s) are the number of distinct prime factors (with multiplicity) in each of the following k integers. %C A323084 a(6)-a(12) found by Carlos Rivera. %C A323084 a(18) > 10^13. - _Giovanni Resta_, Jan 04 2019 %H A323084 Chris Caldwell and G. L. Honaker, Jr., <a href="https://primes.utm.edu/curios/page.php?curio_id=33930">Prime Curio for 4224</a> %e A323084 4224 is a term because 4224 is a 4-digit number whose digits (4,2,2,4) are the number of prime factors (with multiplicity) in each of the following 4 integers; i.e., 4225 = 5^2*13^2 (four prime factors), 4226 = 2*2113 (two prime factors), 4227 = 3*1409 (two prime factors), and 4228 = 2^2*7*151 (four prime factors), therefore (4,2,2,4) -> 4224. %Y A323084 Cf. A000040, A001222, A323083. %K A323084 nonn,base,more %O A323084 1,3 %A A323084 _G. L. Honaker, Jr._, Jan 03 2019 %E A323084 a(13)-a(17) from _Giovanni Resta_, Jan 04 2019