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 A174232 #9 May 16 2022 11:13:29
%S A174232 1,0,-2,-5,-1,-6,-12,-5,-13,-22,-12,-1,-13,-26,-12,-27,-11,-28,-46,
%T A174232 -65,-45,-66,-88,-111,-87,-112,-86,-113,-141,-112,-142,-111,-143,-176,
%U A174232 -142,-107,-71,-108,-70,-31,9,-32,10,53,97,52,98,51,99,148,198,147,199,146
%N A174232 a(n) = a(n-1) - (-1)^n*n if (A004001(n) mod 3) = 1, otherwise a(n-1) + (-1)^n*n.
%H A174232 G. C. Greubel, <a href="/A174232/b174232.txt">Table of n, a(n) for n = 0..1000</a>
%F A174232 a(n) = a(n-1) - (-1)^n*n if (A004001(n) mod 3) = 1, otherwise a(n-1) + (-1)^n*n, with a(0) = 1 and a(1) = 0.
%t A174232 HC[n_]:= HC[n]= If[n<3, Fibonacci[n], HC[HC[n-1]] +HC[n -HC[n-1]]]; (*A004001*)
%t A174232 a[n_]:= a[n]= If[n<2, 1-n, If[Mod[HC[n], 3]==1, a[n-1] -(-1)^n*n, a[n-1] + (-1)^n*n]];
%t A174232 Table[a[n], {n,0,80}]
%o A174232 (Sage)
%o A174232 @CachedFunction
%o A174232 def HC(n): # HC = A004001
%o A174232 if (n<3): return fibonacci(n)
%o A174232 else: return HC(HC(n-1)) +HC(n -HC(n-1))
%o A174232 def A174232(n):
%o A174232 if (n<2): return 1-n
%o A174232 elif (HC(n)%3==1): return A174232(n-1) - (-1)^n*n
%o A174232 else: return A174232(n-1) + (-1)^n*n
%o A174232 [A174232(n) for n in (0..80)] # _G. C. Greubel_, Nov 24 2021
%Y A174232 Cf. A004001, A174218.
%K A174232 sign
%O A174232 0,3
%A A174232 _Roger L. Bagula_, Mar 13 2010
%E A174232 Edited by _G. C. Greubel_, Nov 24 2021