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 A080573 #17 Jun 05 2019 19:39:56 %S A080573 0,0,1,1,2,1,2,1,2,2,1,2,1,3,2,1,3,1,4,2,2,2,0,3,0,1,2,1,4,2,2,2,0,3, %T A080573 0,1,2,1,4,2,2,3,0,4,0,2,1,1,4,2,3,2,1,5,2,3,1,2,3,2,3,1,3,5,3,4,0,2, %U A080573 1,3,2,1,5,3,5,2,1,3,2,4,2,1,5,2,6,2,1,5,2,5,2,0,4,0,6,0 %N A080573 Number of ways writing n as a sum of two distinct Ulam numbers. %C A080573 After about 10^5 terms, the plot of this sequences begins to show some structure. - _T. D. Noe_, Jan 21 2008 %C A080573 When a(n)=1, n is an Ulam number, A002858. A033629 has the terms when a(n)=0. - _Jud McCranie_, Jul 22 2012 %H A080573 T. D. Noe, <a href="/A080573/b080573.txt">Table of n, a(n) for n=1..10000</a> %H A080573 T. D. Noe, <a href="http://www.sspectra.com/math/A080573.gif">Plot of 10^5 terms of A080573</a> %H A080573 Rémy Sigrist, <a href="/A080573/a080573.png">Density plot of the first million terms</a> %H A080573 Rémy Sigrist, <a href="/A080573/a080573.txt">C program for A080573</a> %o A080573 (C) See Links section. %Y A080573 Cf. A002858, A033629. %K A080573 easy,nonn %O A080573 1,5 %A A080573 _Naohiro Nomoto_, Feb 22 2003