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 A299756 #9 Feb 23 2018 11:11:26
%S A299756 1,2,3,4,1,2,5,1,3,6,1,4,7,2,3,8,1,5,2,4,9,10,1,6,11,3,4,2,5,1,7,12,1,
%T A299756 2,3,13,1,8,2,6,3,5,14,1,2,4,15,1,9,2,7,1,10,4,5,3,6,16,1,11,2,8,1,3,
%U A299756 4,17,1,2,5,18,3,7,4,6,1,12,19,2,9,20,1,13
%N A299756 Triangle read by rows in which row n is the finite increasing sequence, or set of positive integers, with FDH number n.
%C A299756 Let f(n) = A050376(n) be the n-th number of the form p^(2^k) where p is prime and k >= 0. The FDH number of a set S is Product_{x in S} f(x).
%C A299756 Same as A299755 with rows reversed.
%e A299756 Sequence of sets begins: {}, {1}, {2}, {3}, {4}, {1,2}, {5}, {1,3}, {6}, {1,4}, {7}, {2,3}, {8}, {1,5}, {2,4}, {9}, {10}, {1,6}, {11}, {3,4}, {2,5}, {1,7}, {12}, {1,2,3}, {13}.
%t A299756 FDfactor[n_]:=If[n===1,{},Sort[Join@@Cases[FactorInteger[n],{p_,k_}:>Power[p,Cases[Position[IntegerDigits[k,2]//Reverse,1],{m_}->2^(m-1)]]]]];
%t A299756 nn=200;FDprimeList=Array[FDfactor,nn,1,Union];
%t A299756 FDrules=MapIndexed[(#1->#2[[1]])&,FDprimeList];
%t A299756 Join@@Table[FDfactor[n]/.FDrules,{n,60}]
%Y A299756 Row lengths are A064547.
%Y A299756 Cf. A005117, A050376, A112798, A213925, A246867, A277098, A296150, A299090, A299755, A299757, A299759.
%K A299756 nonn,tabf
%O A299756 1,2
%A A299756 _Gus Wiseman_, Feb 18 2018