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 A229853 #20 Apr 04 2025 14:30:39
%S A229853 1,385,769,1153,1537,1921,2305,2689,3073,3457,3841,4225,4609,4993,
%T A229853 5377,5761,6145,6529,6913,7297,7681,8065,8449,8833,9217,9601,9985,
%U A229853 10369,10753,11137,11521,11905,12289,12673,13057,13441,13825,14209,14593,14977,15361,15745
%N A229853 a(n) = 384*n + 1.
%C A229853 Every composite Fermat number has a divisor of the form 384*n + 1, n > 0.
%H A229853 Arkadiusz Wesolowski, <a href="/A229853/b229853.txt">Table of n, a(n) for n = 0..1000</a>
%H A229853 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fermat_number">Fermat number</a>.
%H A229853 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F A229853 G.f.: (1 + 383*x)/(1 - x)^2.
%F A229853 From _Elmo R. Oliveira_, Apr 04 2025: (Start)
%F A229853 E.g.f.: exp(x)*(1 + 384*x).
%F A229853 a(n) = 2*a(n-1) - a(n-2). (End)
%p A229853 seq(384*n+1, n=0..40);
%t A229853 Table[384*n + 1, {n, 0, 40}]
%o A229853 (Magma) [384*n+1 : n in [0..40]];
%o A229853 (PARI) for(n=0, 40, print1(384*n+1, ", "));
%Y A229853 Cf. A000215, A094358, A229854, A229855, A229856.
%K A229853 nonn,easy
%O A229853 0,2
%A A229853 _Arkadiusz Wesolowski_, Oct 01 2013