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 A080331 #11 Jan 02 2022 14:37:54 %S A080331 0,0,2,3,4,5,6,7,8,9,10,11,12,13,13,15,15,17,13,17,20,20,20,20,20,25, %T A080331 26,27,28,20,20,27,25,33,27,28,36,37,38,27,40,38,42,42,44,40,46,47,48, %U A080331 42,40,51,52,38,53,44,56,56,54,59,55,61,56,53,61,65,65,67,61,69,70 %N A080331 Index in A002858 of the larger of the two Ulam numbers that sum to the n-th Ulam number. %C A080331 The first two terms in this sequence are zero because the Ulam sequence (A002858) is initialized for those terms. The terms of the sum are in A080328 and A080329 and the indices are in A080330 and A080331. %H A080331 Rémy Sigrist, <a href="/A080331/b080331.txt">Table of n, a(n) for n = 1..10000</a> %H A080331 Rémy Sigrist, <a href="/A080331/a080331.gp.txt">PARI program for A080331</a> %e A080331 The 11th Ulam number (26) is the sum of the 6th Ulam number (8) and the 10th Ulam number (18), so a(11)=10. %o A080331 (PARI) See Links section. %Y A080331 Cf. A002858, A080328, A080329, A080330. %K A080331 nonn %O A080331 1,3 %A A080331 _Jud McCranie_, Feb 15 2003