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 A097802 #17 May 29 2025 22:03:48
%S A097802 3,78,153,228,303,378,453,528,603,678,753,828,903,978,1053,1128,1203,
%T A097802 1278,1353,1428,1503,1578,1653,1728,1803,1878,1953,2028,2103,2178,
%U A097802 2253,2328,2403,2478,2553,2628,2703,2778,2853,2928,3003,3078,3153,3228,3303,3378,3453,3528
%N A097802 a(n) = 3*(25*n + 1).
%H A097802 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>.
%H A097802 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F A097802 From _Elmo R. Oliveira_, May 25 2025: (Start)
%F A097802 G.f.: 3*(1 + 24*x)/(1-x)^2.
%F A097802 E.g.f.: 3*exp(x)*(1 + 25*x).
%F A097802 a(n) = 3*A158060(n) for n > 0.
%F A097802 a(n) = 2*a(n-1) - a(n-2). (End)
%t A097802 75*Range[0, 50]+3 (* _Paolo Xausa_, Feb 16 2024 *)
%o A097802 (PARI) a(n)=3*(25*n+1) \\ _Charles R Greathouse IV_, Jul 10 2016
%o A097802 (PARI) my(x='x+O('x^48)); Vec(3*(1+24*x)/(1-x)^2) \\ _Elmo R. Oliveira_, May 25 2025
%Y A097802 Cf. A158060.
%K A097802 nonn,easy
%O A097802 0,1
%A A097802 _George E. Antoniou_, Aug 25 2004
%E A097802 More terms from _Robert G. Wilson v_ and Mark Hudson (mrmarkhudson(AT)hotmail.com), Aug 26 2004
%E A097802 a(45)-a(47) from _Elmo R. Oliveira_, May 25 2025