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 A011585 #14 Apr 12 2020 08:42:25 %S A011585 0,1,-1,-1,1,1,1,1,-1,1,-1,1,-1,-1,-1,-1,1,1,-1,0,1,-1,-1,1,1,1,1,-1, %T A011585 1,-1,1,-1,-1,-1,-1,1,1,-1,0,1,-1,-1,1,1,1,1,-1,1,-1,1,-1,-1,-1,-1,1, %U A011585 1,-1,0,1,-1,-1,1,1,1,1,-1,1,-1,1,-1,-1,-1,-1,1,1,-1,0,1,-1,-1,1 %N A011585 Legendre symbol (n,19). %D A011585 G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers. 3rd ed., Oxford Univ. Press, 1954, p. 68. %H A011585 Harvey P. Dale, <a href="/A011585/b011585.txt">Table of n, a(n) for n = 0..1000</a> %H A011585 <a href="/index/Rec#order_18">Index entries for linear recurrences with constant coefficients</a>, signature (-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1). %t A011585 JacobiSymbol[Range[0,80],19] (* _Harvey P. Dale_, Feb 13 2017 *) %K A011585 sign,mult %O A011585 0,1 %A A011585 _N. J. A. Sloane_