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 A091384 #9 Mar 14 2018 03:51:25
%S A091384 0,-1,-5,-1,-3,0,0,-8,0,-1,0,-7,-2,-6,-1,0,0,-5,-6,0,0,-7,-2,0,-2,-3,
%T A091384 -1,0,-1,-5,-5,-7,-2,-11,0,-1,0,0,-1,-2,-10,0,0,-6,-3,-1,-5,-5,-6,-5,
%U A091384 0,-1,-5,-7,-2,-5,-1,-5,0,-2,-2,-7,0,-7,-9,-4,-4,-8,-5,-13,0,-4,-4,-7,-17,0,-3,0,-5,-1,-3,0,-17,0,-7,-6,-1,-2,-3,-3,0
%N A091384 Members of the difference sequence (A091381) of the sequence of largest quadratic "mixed" residues modulo the primes (A091380) where the latter is non-monotonic.
%C A091384 The negative values are either primes or composites (Cf. A088200).
%H A091384 Ferenc Adorjan, <a href="http://web.axelero.hu/fadorjan/qrp.pdf">The sequence of largest quadratic residues modulo the primes</a>
%o A091384 (PARI) {/* The difference sequence values where the sequence of the largest "mixed" QR modulo the primes is non-monotonic */ lqxr_nm_d(to)=local(v=[],k,r,q,p,e=1,n=0,i=1); while(n<to,i+=1;p=prime(i);k=p-1;r=p%4-2; while(kronecker(k,p)<>r,k-=1); if(k-e<=0,v=concat(v,k-e);n+=1);e=k); print(i);print(v) }
%Y A091384 Cf. A091380, A091381, A091382, A091383, A091385, A088190, A088196, A088200.
%K A091384 easy,sign
%O A091384 1,3
%A A091384 Ferenc Adorjan (fadorjan(AT)freemail.hu)