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 A145440 #15 Sep 08 2022 08:45:38 %S A145440 17,73,521,262153,1073741833,144115188075855881,73786976294838206473, %T A145440 273406340597876490546562778389702670669146178861651554553221325801244124899921990402939147127881737 %N A145440 Primes of the form 8^k + 9. %C A145440 8^k + 9 is prime for k = 1, 2, 3, 6, 10, 19, 22, ... %H A145440 Vincenzo Librandi, <a href="/A145440/b145440.txt">Table of n, a(n) for n = 1..9</a> %e A145440 For k=1, 8^1 + 9 = 17; %e A145440 for n=2, 8^2 + 9 = 73; %e A145440 for n=3, 8^3 + 9 = 521. %t A145440 Select[8^Range[120]+9,PrimeQ] (* _Harvey P. Dale_, Jan 18 2011 *) %o A145440 (Magma) [a: n in [0..200] | IsPrime(a) where a is 8^n+9]; %Y A145440 A subsequence of A104070. Cf. A057196. %K A145440 nonn %O A145440 1,1 %A A145440 _Vincenzo Librandi_, Mar 11 2009