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 A317659 #9 Sep 11 2018 21:18:26
%S A317659 1,1,0,1,1,0,1,3,1,0,1,6,5,1,0,1,10,17,7,1,0,1,15,43,33,9,1,0,1,21,92,
%T A317659 118,55,11,1,0,1,28,174,341,252,82,13,1,0,1,36,302,845,935,463,115,15,
%U A317659 1,0,1,45,490,1864,2921,2103,769,153,17,1,0,1,55,755
%N A317659 Regular triangle where T(n,k) is the number of distinct free pure symmetric multifunctions (with empty expressions allowed) with one atom, n positions, and k leaves.
%H A317659 Mathematica Reference, <a href="http://reference.wolfram.com/mathematica/ref/Orderless.html">Orderless</a>
%e A317659 The T(5,3) = 5 expressions are o[o[o]], o[o,o[]], o[][o,o], o[o][o], o[o,o][].
%e A317659 Triangle begins:
%e A317659 1
%e A317659 1 0
%e A317659 1 1 0
%e A317659 1 3 1 0
%e A317659 1 6 5 1 0
%e A317659 1 10 17 7 1 0
%e A317659 1 15 43 33 9 1 0
%e A317659 1 21 92 118 55 11 1 0
%e A317659 1 28 174 341 252 82 13 1 0
%e A317659 1 36 302 845 935 463 115 15 1 0
%e A317659 1 45 490 1864 2921 2103 769 153 17 1 0
%e A317659 1 55 755 3755 7981 8012 4145 1187 197 19 1 0
%t A317659 maxUsing[n_]:=If[n==1,{"o"},Join@@Cases[Table[PR[k,n-k-1],{k,n-1}],PR[h_,g_]:>Join@@Table[Apply@@@Tuples[{maxUsing[h],Union[Sort/@Tuples[maxUsing/@p]]}],{p,IntegerPartitions[g]}]]];
%t A317659 Table[Length[Select[maxUsing[n],Length[Position[#,"o"]]==k&]],{n,12},{k,n}]
%Y A317659 Cf. A001003, A052893, A053492, A255906, A277996, A279944, A280000.
%Y A317659 Cf. A317652, A317653, A317654, A317655, A317656, A317676.
%K A317659 nonn,tabl
%O A317659 1,8
%A A317659 _Gus Wiseman_, Aug 03 2018