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 A053208 #25 Oct 27 2023 22:00:45
%S A053208 0,3,10,24,52,108,220,444,892,1788,3580,7164,14332,28668,57340,114684,
%T A053208 229372,458748,917500,1835004,3670012,7340028,14680060,29360124,
%U A053208 58720252,117440508,234881020,469762044,939524092,1879048188
%N A053208 Row sums of A053207.
%H A053208 G. C. Greubel, <a href="/A053208/b053208.txt">Table of n, a(n) for n = 0..1000</a>
%H A053208 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2).
%F A053208 a(0) = 0, a(1) = 3, a(n+1) = 2*a(n) + 4, for n >= 1.
%F A053208 a(n) = 7*2^(n-1) - 4, n >= 1.
%F A053208 G.f.: x*(x + 3)/((x - 1)*(2*x - 1)). - _Chai Wah Wu_, Jul 24 2020
%t A053208 Join[{0},NestList[2#+4&,3,30]] (* _Harvey P. Dale_, Nov 08 2013 *)
%t A053208 Join[{0}, Table[7*2^(n-1) -4, {n,50}]] (* _G. C. Greubel_, Sep 03 2018 *)
%o A053208 (PARI) concat([0], vector(50, n, 7*2^(n-1) -4)) \\ _G. C. Greubel_, Sep 03 2018
%o A053208 (Magma) [0] cat [7*2^(n-1) -4: n in [1..50]]; // _G. C. Greubel_, Sep 03 2018
%Y A053208 Cf. A053207, A053209.
%K A053208 nonn,easy
%O A053208 0,2
%A A053208 _Asher Auel_, Dec 13 1999