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 A120136 #14 May 13 2023 19:20:20
%S A120136 7,10,15,23,34,51,77,115,173,259,389,583,875,1312,1968,2952,4428,6642,
%T A120136 9963,14945,22417,33626,50439,75658,113487,170231,255346,383019,
%U A120136 574529,861793,1292690,1939035,2908552,4362828,6544242,9816363,14724545
%N A120136 a(n) = 7 + floor(Sum_{j=1..n-1} a(j) / 2).
%H A120136 Harvey P. Dale, <a href="/A120136/b120136.txt">Table of n, a(n) for n = 1..1000</a>
%t A120136 nxt[{t_,a_}] := Module[{c=7+Floor[t/2]},{t+c,c}];
%t A120136 NestList[nxt,{7,7},40][[All,2]] (* _Harvey P. Dale_, Jan 13 2017 *)
%o A120136 (SageMath)
%o A120136 @CachedFunction
%o A120136 def A120136(n): return 7 +sum(A120136(k) for k in range(1,n))//2
%o A120136 [A120136(n) for n in range(1,60)] # _G. C. Greubel_, May 08 2023
%Y A120136 Cf. A073941, A072493, A112088, A120134, A120135, A120137 - A120209.
%K A120136 nonn
%O A120136 1,1
%A A120136 _Graeme McRae_, Jun 10 2006