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 A120149 #9 Jun 05 2023 08:52:53
%S A120149 2,3,4,5,7,9,12,16,21,28,38,50,67,89,119,159,212,282,376,502,669,892,
%T A120149 1189,1586,2114,2819,3759,5012,6682,8910,11880,15840,21120,28160,
%U A120149 37546,50062,66749,88999,118665,158220,210960,281280,375040,500053,666738
%N A120149 a(n) = 2 + floor((1 + Sum_{j=1..n-1} a(j))/3).
%H A120149 G. C. Greubel, <a href="/A120149/b120149.txt">Table of n, a(n) for n = 1..1000</a>
%t A120149 f[s_] := Append[s, Floor[(7 + Plus @@ s)/3]]; Nest[f, {2}, 44] (* _Robert G. Wilson v_, Jul 08 2006 *)
%o A120149 (SageMath)
%o A120149 @CachedFunction
%o A120149 def A120149(n): return 2 + (1+sum(A120149(k) for k in range(1,n)))//3
%o A120149 [A120149(n) for n in range(1, 61)] # _G. C. Greubel_, Jun 04 2023
%Y A120149 Cf. A072493, A073941, A112088.
%K A120149 nonn
%O A120149 1,1
%A A120149 _Graeme McRae_, Jun 10 2006
%E A120149 More terms from _Robert G. Wilson v_, Jul 08 2006