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 A098147 #5 Jul 07 2023 21:03:27 %S A098147 5,11,3,1,1,1,1,1,13,3,7,7,15,13,3,3,15,7,1,19,3,19,13,29,7,7,3,27,13, %T A098147 3,1,9,9,9,27,7,3,7,49,55,81,3,3,9,7,11,69,7,19,13,39,7,1,3,13,13,39, %U A098147 77,27,63,31,51,19,9,27,3,1,39,19,41,21,67,37,63,69,33,3,9,37,67,121,9,21 %N A098147 Difference between first odd semiprime > 10^n and 10^n. %H A098147 Dario Alpern, <a href="https://www.alpertron.com.ar/ECM.HTM">Factorization using the Elliptic Curve Method.</a> %F A098147 a(n)=A098146(n)-10^n. %e A098147 a(2)=11: The first odd semiprime following 10^2 is 111=3*37; 111-100=11. %Y A098147 Cf. A098146, A033873 difference between first prime > 10^n and 10^n. %K A098147 nonn %O A098147 1,1 %A A098147 _Hugo Pfoertner_, Aug 28 2004