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 A321692 #5 Nov 18 2018 10:04:26 %S A321692 1,0,1,0,0,0,0,1,1,1,1,1,1,0,1,1,0,1,1,1,0,0,0,0,1,0,1,0,0,1,0,0,1,0, %T A321692 0,0,0,1,1,0,0,1,1,0,1,0,1,1,0,1,1,0,1,0,1,0,1,0,1,0,1,1,0,0,1,0,1,1, %U A321692 0,1,1,1,1,1,1,1,1,1,1,0,0,1,1,1,1,0,0 %N A321692 Digits of the 2-adic integer exp(-4). %C A321692 This is the multiplicative inverse of A320815. %H A321692 Wikipedia, <a href="https://en.wikipedia.org/wiki/P-adic_number">p-adic number</a> %F A321692 a(n) = (A321689(n+1) - A321689(n))/2^n. %e A321692 exp(-4) = ...00110000100100101000011101101111110000101. %o A321692 (PARI) a(n) = lift(sum(i=0, n-(n>=2), Mod(4^i/i!, 2^(n+1))))\2^n %o A321692 (PARI) a(n) = lift(exp(-4 + O(2^(n+1))))\2^n; %Y A321692 Cf. A320815, A321689. %K A321692 nonn,base %O A321692 0,1 %A A321692 _Jianing Song_, Nov 17 2018