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 A330726 #5 Jan 04 2020 09:52:40 %S A330726 1,1,2,3,7,17,54,199,869,4341,24514,154187 %N A330726 Number of balanced reduced multisystems of maximum depth whose atoms are positive integers summing to n. %C A330726 A balanced reduced multisystem is either a finite multiset, or a multiset partition with at least two parts, not all of which are singletons, of a balanced reduced multisystem. %e A330726 The a(1) = 1 through a(5) = 17 multisystems (commas elided): %e A330726 {1} {2} {3} {4} {5} %e A330726 {11} {12} {22} {23} %e A330726 {{1}{11}} {13} {14} %e A330726 {{1}{12}} {{1}{13}} %e A330726 {{2}{11}} {{1}{22}} %e A330726 {{{1}}{{1}{11}}} {{2}{12}} %e A330726 {{{11}}{{1}{1}}} {{3}{11}} %e A330726 {{{1}}{{1}{12}}} %e A330726 {{{11}}{{1}{2}}} %e A330726 {{{1}}{{2}{11}}} %e A330726 {{{12}}{{1}{1}}} %e A330726 {{{2}}{{1}{11}}} %e A330726 {{{{1}}}{{{1}}{{1}{11}}}} %e A330726 {{{{1}}}{{{11}}{{1}{1}}}} %e A330726 {{{{1}{1}}}{{{1}}{{11}}}} %e A330726 {{{{1}{11}}}{{{1}}{{1}}}} %e A330726 {{{{11}}}{{{1}}{{1}{1}}}} %t A330726 sps[{}]:={{}};sps[set:{i_,___}]:=Join@@Function[s,Prepend[#,s]&/@sps[Complement[set,s]]]/@Cases[Subsets[set],{i,___}]; %t A330726 mps[set_]:=Union[Sort[Sort/@(#/.x_Integer:>set[[x]])]&/@sps[Range[Length[set]]]]; %t A330726 totm[m_]:=Prepend[Join@@Table[totm[p],{p,Select[mps[m],1<Length[#]<Length[m]&]}],m]; %t A330726 Table[Sum[Length[Select[totm[m],Depth[#]==If[Length[m]<=1,2,Length[m]]&]],{m,IntegerPartitions[n]}],{n,0,5}] %Y A330726 The case with all atoms equal to 1 is A000111. %Y A330726 The non-maximal version is A330679. %Y A330726 A tree version is A320160. %Y A330726 Cf. A000669, A002846, A005121, A141268, A196545, A213427, A317145, A318813, A330663, A330665, A330675, A330676, A330728. %K A330726 nonn,more %O A330726 0,3 %A A330726 _Gus Wiseman_, Jan 03 2020