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 A258073 #32 Sep 08 2022 08:46:12
%S A258073 157115,314229,628457,1256913,2513825,5027649,10055297,20110593,
%T A258073 40221185,80442369,160884737,321769473,643538945,1287077889,
%U A258073 2574155777,5148311553,10296623105,20593246209,41186492417,82372984833,164745969665,329491939329
%N A258073 a(n) = 1 + 78557*2^n.
%C A258073 78557 is the (conjectured) smallest Sierpiński number (A076336). This means that every number in the current sequence is composite.
%C A258073 Every number in the sequence is divisible by some number in {3, 5, 7, 13, 19, 37, 73}.
%H A258073 Reinhard Zumkeller, <a href="/A258073/b258073.txt">Table of n, a(n) for n = 1..1000</a>
%H A258073 W. Sierpiński, <a href="http://dx.doi.org/10.5169/seals-20713">Sur un problème concernant les nombres k * 2^n + 1</a>, Elem. Math., 15 (1960), pp. 73-74.
%H A258073 Wikipedia, <a href="http://en.wikipedia.org/wiki/Sierpinski_number">Sierpinski Number</a>
%H A258073 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2).
%F A258073 G.f.: x*(157115-157116*x)/((1-2*x)*(1-x)). - _Vincenzo Librandi_, May 19 2015
%F A258073 a(n) = 3*a(n-1)-2*a(n-2). - _Wesley Ivan Hurt_, Apr 26 2021
%t A258073 Table[1 + 78557 2^n, {n, 1, 25}] (* _Vincenzo Librandi_, May 19 2015 *)
%o A258073 (Sage) [78557*2^n+1 for n in [1..25]]
%o A258073 (Magma) [1+78557*2^n: n in [1..25]]; // _Vincenzo Librandi_ May 19 2015
%o A258073 (Haskell)
%o A258073 a258073 = (+ 1) . (* 78557) . (2 ^) -- _Reinhard Zumkeller_, May 19 2015
%Y A258073 Cf. A076336.
%Y A258073 Cf. A258091 (smallest prime factors).
%K A258073 nonn,easy
%O A258073 1,1
%A A258073 _Tom Edgar_, May 18 2015