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 A256910 #6 Apr 14 2015 11:05:48 %S A256910 0,1,2,3,1,2,6,1,2,3,10,1,2,3,1,15,1,2,3,1,2,21,1,2,3,1,2,6,28,1,2,3, %T A256910 1,2,6,1,36,1,2,3,1,2,6,1,2,45,1,2,3,1,2,6,1,2,3,55,1,2,3,1,2,6,1,2,3, %U A256910 10,66,1,2,3,1,2,6,1,2,3,10,1,78,1,2,3,1 %N A256910 Trace of the enhanced triangular-number representation of n. %C A256910 See A256909 for definitions. %H A256910 Clark Kimberling, <a href="/A256910/b256910.txt">Table of n, a(n) for n = 0..1000</a> %e A256910 R(0) = 0, trace = 0; %e A256910 R(1) = 1, trace = 1; %e A256910 R(2) = 2, trace = 2; %e A256910 R(3) = 3, trace = 3; %e A256910 R(4) = 3 + 1, trace = 1; %e A256910 R(5) = 3 + 2, trace = 2; %e A256910 R(6) = 6, trace = 6; %e A256910 R(119) = 105 + 10 + 3 + 1, trace = 1. %t A256910 b[n_] := n (n + 1)/2; bb = Insert[Table[b[n], {n, 0, 200}], 2, 3] %t A256910 s[n_] := Table[b[n], {k, 1, n + 1}]; %t A256910 h[1] = {0, 1, 2}; h[n_] := Join[h[n - 1], s[n]]; %t A256910 g = h[200]; r[0] = {0}; %t A256910 r[n_] := If[MemberQ[bb, n], {n}, Join[{g[[n]]}, r[n - g[[n]]]]]; %t A256910 t = Table[r[n], {n, 0, 120}] (*A256909 before concatenation*) %t A256910 Flatten[t] (*A256909*) %t A256910 Table[Last[r[n]], {n, 0, 120}] (*A256910*) %t A256910 Table[Length[r[n]], {n, 0, 120}] (*A256911*) %Y A256910 Cf. A000217, A256909 (definitions), A256911 (number of terms), A255974 (minimal alternating triangular-number representations). %K A256910 nonn,easy %O A256910 0,3 %A A256910 _Clark Kimberling_, Apr 13 2015