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 A331686 #5 Feb 01 2020 14:39:45 %S A331686 1,2,4,8,17,41,103,280,793,2330,6979,21291 %N A331686 Number of lone-child-avoiding locally disjoint rooted identity trees whose leaves are integer partitions whose multiset union is an integer partition of n. %C A331686 A rooted tree is locally disjoint if no child of any vertex has branches overlapping the branches of any other (unequal) child of the same vertex. Lone-child-avoiding means there are no unary branchings. In an identity tree, all branches of any given vertex are distinct. %e A331686 The a(1) = 1 through a(5) = 17 trees: %e A331686 (1) (2) (3) (4) (5) %e A331686 (11) (12) (13) (14) %e A331686 (111) (22) (23) %e A331686 ((1)(2)) (112) (113) %e A331686 (1111) (122) %e A331686 ((1)(3)) (1112) %e A331686 ((2)(11)) (11111) %e A331686 ((1)((1)(2))) ((1)(4)) %e A331686 ((2)(3)) %e A331686 ((1)(22)) %e A331686 ((3)(11)) %e A331686 ((2)(111)) %e A331686 ((1)((1)(3))) %e A331686 ((2)((1)(2))) %e A331686 ((11)((1)(2))) %e A331686 ((1)((2)(11))) %e A331686 ((1)((1)((1)(2)))) %t A331686 sps[{}]:={{}};sps[set:{i_,___}]:=Join@@Function[s,Prepend[#,s]&/@sps[Complement[set,s]]]/@Cases[Subsets[set],{i,___}]; %t A331686 mps[set_]:=Union[Sort[Sort/@(#/.x_Integer:>set[[x]])]&/@sps[Range[Length[set]]]]; %t A331686 disjointQ[u_]:=Apply[And,Outer[#1==#2||Intersection[#1,#2]=={}&,u,u,1],{0,1}]; %t A331686 mpti[m_]:=Prepend[Join@@Table[Select[Union[Sort/@Tuples[mpti/@p]],UnsameQ@@#&&disjointQ[#]&],{p,Select[mps[m],Length[#]>1&]}],m]; %t A331686 Table[Sum[Length[mpti[m]],{m,Sort/@IntegerPartitions[n]}],{n,8}] %Y A331686 The non-identity version is A331678. %Y A331686 The case where the leaves are all singletons is A316694. %Y A331686 Identity trees are A004111. %Y A331686 Locally disjoint identity trees are A316471. %Y A331686 Locally disjoint enriched identity p-trees are A331684. %Y A331686 Lone-child-avoiding locally disjoint rooted semi-identity trees are A212804. %Y A331686 Cf. A000669, A001678, A005804, A141268, A300660, A316697, A319312, A331679, A331683, A331783, A331874, A331875. %K A331686 nonn,more %O A331686 1,2 %A A331686 _Gus Wiseman_, Jan 31 2020