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 A242390 #9 Apr 04 2015 21:49:03 %S A242390 0,0,1,0,3,5,1,8,0,12,7,18,1,14,11,27,31,5,3,17,42,0,50,15,35,40,27, %T A242390 33,1,56,65,9,79,4,30,23,60,70,88,11,106,127,17,98,41,0,122,141,9,37, %U A242390 77,163,119,20,0,57,182,168,98,92,202,21,199,154,6,129,227,81,2,265 %N A242390 Lexicographically earliest nonnegative integer sequence such that for every positive integer d, the sequence a(n+d)-a(n), n>=0 is injective. %C A242390 a(0)=0; a(n)= smallest nonnegative integer which is different from a(n-d)-a(k+d)-a(k) for every k=0..n-2 and d=1..n-k-1. %C A242390 lim sup a(n)*log(n)*log(log(n))/n^2 seems to be positive and finite, maybe 1/pi. %C A242390 Is the sequence surjective? %H A242390 Matthieu Pluntz, <a href="/A242390/b242390.txt">Table of n, a(n) for n = 0..2100</a> %H A242390 Matthieu Pluntz, <a href="/A242390/a242390.m.txt">MATLAB program</a> %e A242390 Determining a(4) : 0=a(3)+a(1)-a(0);1=a(3)+a(2)-a(1);2=a(2)+a(2)-a(0) are excluded, a(4)=3 is not. %K A242390 nonn %O A242390 0,5 %A A242390 _Matthieu Pluntz_, May 12 2014