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 A181863 #31 Apr 20 2024 10:02:00 %S A181863 3,11,41,101 %N A181863 Decimal sturdy primes: primes p such that sum of digits of k*p for any positive integer k is at least the sum of digits of p. %C A181863 Prime elements of A181862. %C A181863 Primes p such that A007953(p) = A077196(p). %C A181863 Contains prime repunits A004022 as a subsequence. %C A181863 a(5) > 1.4*10^7. - _Giovanni Resta_, Sep 18 2018 %C A181863 From _Jason Yuen_, Mar 25 2024: (Start) %C A181863 For all x>log_10(p), 1+A007953(p-(10^x mod p)) >= A007953(p). This follows from the fact that 10^x+p-(10^x mod p) is a multiple of p. %C A181863 a(5) > 2*10^11. See a181863_2e11.txt for more details. (End) %H A181863 Trevor Clokie, Thomas F. Lidbetter, Antonio Molina Lovett, Jeffrey Shallit, and Leon Witzman, <a href="https://doi.org/10.1016/j.tcs.2022.05.029">Computational Aspects of Sturdy and Flimsy Numbers</a>, Theoretical Computer Science, Vol. 927 (2022), pp. 65-86; <a href="https://arxiv.org/abs/2002.02731">arXiv preprint</a>, arXiv:2002.02731 [cs.DS], 2020. %H A181863 Jason Yuen, <a href="/A181863/a181863.txt">a181863_2e11.txt</a>. This file shows that a(5) > 2*10^11. %Y A181863 Cf. A004022, A007953, A077196, A143027, A181862. %K A181863 nonn,base,more,hard %O A181863 1,1 %A A181863 _Max Alekseyev_, Nov 14 2010