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 A363353 #16 Aug 24 2023 10:15:48 %S A363353 3,4,7,8,10,15,16,21,27,30,37,42,43,54,66,77,96,114,130,132,155,156, %T A363353 168,182,213,294 %N A363353 Numbers k such that 10^k + 3 is a semiprime. %C A363353 a(27) >= 306. - _Amiram Eldar_, Aug 17 2023 %e A363353 a(3) = 7 is a term because 10^7 + 3 = 13 * 769231 is a semiprime. %p A363353 select(t -> numtheory:-bigomega(10^t+3) = 2, [$1..70]); %Y A363353 Cf. A001358, A049054, A363352. %K A363353 nonn,more %O A363353 1,1 %A A363353 _Robert Israel_, Aug 16 2023 %E A363353 a(18)-a(26) from _Amiram Eldar_, Aug 17 2023