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 A180433 #24 Oct 10 2022 01:12:23
%S A180433 0,0,1,1,0,1,1,0,1,1,1,1,0,0,0,0,0,0,1,0,0,1,0,1,0,1,0,1,1,1,0,1,1,1,
%T A180433 0,1,1,1,1,0,1,0,0,1,0,1,1,1,0,0,1,1,1,1,0,1,1,1,0,0,1,0,1,1,0,0,1,1,
%U A180433 1,0,1,1,0,0,1,1,1,0,0,1,1,0,0,1,1,1,0,1,0,1,1,1,0,1,0,0,0,1,1,1,1,1,1,1,0
%N A180433 Binary string formed from the binary expansion of Pi by exchanging 0's and 1's.
%C A180433 Binary complement of A004601.
%C A180433 May be converted to a decimal number in several ways, depending on where the binary point is inserted: .0011011011110... = 1-Pi/4, 0.011011011110... = 2-Pi/2 (see A180434), 00.11011011110... = 4-Pi.
%H A180433 Tarun Agarwal, <a href="/A180433/b180433.txt">Table of n, a(n) for n = 1..999</a>
%t A180433 RealDigits[Pi,2,120][[1]]/.{1->0,0->1} (* _Harvey P. Dale_, Apr 02 2015 *)
%Y A180433 Cf. A004601, A180434.
%K A180433 base,cons,easy,nonn
%O A180433 1,1
%A A180433 _Jonathan Vos Post_, Sep 05 2010
%E A180433 Verified and edited by _N. J. A. Sloane_, Sep 28 2010