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 A340902 #5 Jan 26 2021 08:05:22 %S A340902 63,621,6101,11333,59511,172473 %N A340902 Distance from the largest prime with less than 10^n decimal digits to 10^(10^n-1). %C A340902 The prime number related to a(n) is the prime immediately preceding the prime related to A096548(n). %C A340902 a(5) and a(6) appear to have been first found by Patrick De Geest. %H A340902 factordb.com, <a href="http://factordb.com/index.php?id=1100000000212915894">10^999 - 6101</a>, contains primality certificate related to a(3). %H A340902 factordb.com, <a href="http://factordb.com/index.php?id=1100000000605958068">10^9999 - 11333</a>, contains primality certificate related to a(4). %H A340902 Henri Lifchitz, Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=10%5E99999-59511">10^99999 - 59511</a>, related to a(5). %H A340902 Henri Lifchitz, Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=10%5E999999-172473">10^999999 - 172473</a>, related to a(6). %H A340902 Wikipedia, <a href="https://de.wikipedia.org/wiki/Titanische_Primzahl">Titanische Primzahl</a>, in German. %F A340902 a(n) = 10^(10^n-1) - precprime(10^(10^n-1)) = A064722(10^A002283(n)). %e A340902 a(4) = 11333 because 10^9999 - 11333 is the largest prime not exceeding 10^9999. %e A340902 a(5) = 59511 because 10^99999 - 59511 is the largest prime not exceeding 10^99999. %Y A340902 Cf. A033874, A096548. %K A340902 nonn,base,more,hard %O A340902 1,1 %A A340902 _Jeppe Stig Nielsen_, Jan 26 2021