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 A124017 #9 Oct 11 2019 11:35:08
%S A124017 45,90,26820,26925,30705,31710,33375,63420,63570,71805,83865,93075,
%T A124017 103185,127140,134025,148050,170460,202635,211035,223305,269505,
%U A124017 297225,303660,329175,335625,362505,387975,405270,405405,406425,409755,463335
%N A124017 Numbers n for which 2n-1, 4n-1, 8n-1, 16n-1 and 32n-1 are primes.
%H A124017 Harvey P. Dale, <a href="/A124017/b124017.txt">Table of n, a(n) for n = 1..1000</a>
%t A124017 Select[15*Range[40000], And @@ PrimeQ /@ ({2, 4, 8, 16, 32}*# - 1) &] (* _Ray Chandler_, Nov 22 2006 *)
%t A124017 Select[15*Range[31000],AllTrue[#*2^Range[5]-1,PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Aug 05 2019 *)
%Y A124017 Cf. A006254, A124485, A124493, A124494, A125113, A124514, A124515, A124516.
%K A124017 nonn
%O A124017 1,1
%A A124017 _Artur Jasinski_, Nov 04 2006