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 A120143 #13 May 13 2023 19:20:39
%S A120143 17,26,39,58,87,131,196,294,441,662,993,1489,2234,3351,5026,7539,
%T A120143 11309,16963,25445,38167,57251,85876,128814,193221,289832,434748,
%U A120143 652122,978183,1467274,2200911,3301367,4952050,7428075,11142113,16713169
%N A120143 a(n) = 17 + floor( (1 + Sum_{j=0..n-1} a(j))/2 ).
%H A120143 Harvey P. Dale, <a href="/A120143/b120143.txt">Table of n, a(n) for n = 1..1000</a>
%t A120143 nxt[{t_,a_}]:=Module[{c=17+Floor[(1+t)/2]},{t+c,c}]; NestList[nxt,{17,17},60][[All,2]] (* _Harvey P. Dale_, Dec 25 2020 *)
%o A120143 (SageMath)
%o A120143 @CachedFunction
%o A120143 def A120143(n): return 17 + (1 +sum(A120143(k) for k in range(1,n)))//2
%o A120143 [A120143(n) for n in range(1,60)] # _G. C. Greubel_, May 11 2023
%Y A120143 Cf. A073941, A072493, A112088, A120134 - A120142, A120144 - A120209.
%K A120143 nonn
%O A120143 1,1
%A A120143 _Graeme McRae_, Jun 10 2006