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 A071374 #17 May 15 2025 00:50:07
%S A071374 1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,0,1,1,0,1,1,
%T A071374 1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,0,1,1,0,1,1,1,1,
%U A071374 1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,0,1,1,0,1,1,1
%N A071374 0 iff n is of the form 4^a*(8k+7), otherwise 1.
%C A071374 0 iff n is not the sum of three squares.
%H A071374 Jean-Paul Allouche and Jeffrey Shallit, <a href="https://www.cs.uwaterloo.ca/~shallit/Papers/as0.ps">The ring of k-regular sequences</a>, preprint.
%H A071374 Jean-Paul Allouche and Jeffrey Shallit, <a href="https://doi.org/10.1016/0304-3975(92)90001-V">The ring of k-regular sequences</a>, Theoretical Computer Sci., Vol. 98 (1992), pp. 163-197.
%H A071374 <a href="/index/Ar#2-automatic">Index entries for 2-automatic sequences</a>.
%F A071374 From _Amiram Eldar_, May 15 2025: (Start)
%F A071374 a(n) = 1 - A072401(n);
%F A071374 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 5/6. (End)
%o A071374 (PARI) a(n) = if(n, (n >> (2*valuation(n, 4))) % 8 < 7, 1); \\ _Amiram Eldar_, May 15 2025
%Y A071374 1's complement to A072401. Cf. A071377.
%K A071374 nonn,easy
%O A071374 0,1
%A A071374 _N. J. A. Sloane_, Jun 12 2002