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 A068651 #19 Jul 27 2025 08:43:30 %S A068651 929,9222229,9222222222229 %N A068651 Primes in which a string of 2's is sandwiched between two 9's. %C A068651 The next term consists of 109 2's sandwiched between two 9's. - _Sascha Kurz_, Mar 27 2002 %H A068651 Amiram Eldar, <a href="/A068651/b068651.txt">Table of n, a(n) for n = 1..4</a> %H A068651 Patrick De Geest, <a href="http://www.worldofnumbers.com/deplat.htm#pdp929">PDP Reference Table - 929</a>. %H A068651 Makoto Kamada, <a href="https://stdkmd.net/nrr/9/92229.htm#prime">Prime numbers of the form 922...229</a>. %H A068651 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>. %F A068651 a(n) = (830*10^A056265(n) + 61)/9 = (83*10^(A082718(n)-1) + 61)/9. [corrected by _Amiram Eldar_, Jul 27 2025] %Y A068651 Cf. A068645, A068646, A068647, A068648, A068649, A068650, A056265, A082718. %K A068651 base,nonn,hard %O A068651 1,1 %A A068651 _Amarnath Murthy_, Feb 28 2002 %E A068651 Edited by _Ray Chandler_, Oct 20 2010 %E A068651 Edited by _Ray Chandler_, Nov 05 2014