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 A007648 M3079 #26 Jul 08 2025 17:05:36 %S A007648 1,3,21,23,842,1683,3401,16839,49963,60239,150940,155928 %N A007648 n*18^n + 1 is a prime. %C A007648 a(13) > 203597. - _Ray Chandler_, Apr 10 2016 %D A007648 H. Dubner, Generalized Cullen numbers, J. Rec. Math., 21 (No. 3, 1989), 190-191. %D A007648 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %t A007648 k = 0; While[k < 10001, If[PrimeQ[k*18^k + 1], Print@ k]; k++] (* _Robert G. Wilson v_, Aug 19 2013 *) %K A007648 nonn,hard %O A007648 1,2 %A A007648 _N. J. A. Sloane_ %E A007648 Error in description corrected 8/97. %E A007648 a(7) from _Robert G. Wilson v_, Dec 10 2012 %E A007648 a(8)-a(10) from _Giovanni Resta_, Aug 21 2013 %E A007648 a(11)-a(12) from Loeh link by _Ray Chandler_, Apr 10 2016