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 A097293 #12 May 09 2024 11:56:37 %S A097293 1,2,3,1,2,4,1,2,5,1,3,4,1,2,6,1,3,5,2,3,4,1,2,7,1,3,6,1,4,5,2,3,5,1, %T A097293 2,8,1,3,7,1,4,6,2,3,6,2,4,5,1,2,9,1,3,8,1,4,7,1,5,6,2,3,7,2,4,6,3,4, %U A097293 5,1,2,10,1,3,9,1,4,8,1,5,7,2,3,8,2,4,7,2,5,6,3,4,6,1,2,11,1,3,10,1,4,9,1,5,8 %N A097293 Contains exactly once every triple i,j,k such that 0<i<j<k. %H A097293 Robert Israel, <a href="/A097293/b097293.txt">Table of n, a(n) for n = 1..10092</a> (triples with sum <= 52) %F A097293 Terms are lexically ordered in triples by sum: 1 2 3 (sum = 6) 1 2 4 (sum = 7) 1 2 5, then 1 3 4 (two triples having sum = 8), etc. %p A097293 f:= proc(n) local i,j; %p A097293 seq(seq(op([i,j,n-i-j]),j = i+1 .. (n-i-1)/2),i=1..n/3); %p A097293 end proc: %p A097293 map(f, [$1..20]); # _Robert Israel_, May 09 2024 %o A097293 (PARI) a_rows(N) = [[Vec(e)+[0,1,2] |e<-partitions(n,,[3,3])] |n<-[3..N+2]]; \\ _Ruud H.G. van Tol_, May 09 2024 %Y A097293 Cf. A001399 (runlengths of sums), A098294. %K A097293 nonn,look %O A097293 1,2 %A A097293 _Clark Kimberling_, Aug 05 2004