cp's OEIS Frontend

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.

Showing 1-3 of 3 results.

A321254 Regular triangle where T(n,k) is the number of non-isomorphic connected multiset partitions of weight n with multiset density -1 <= k <= n-2.

Original entry on oeis.org

1, 3, 0, 6, 0, 0, 16, 1, 0, 0, 37, 3, 0, 0, 0, 105, 18, 2, 0, 0, 0, 279, 68, 7, 0, 0, 0, 0, 817, 293, 46, 3, 0, 0, 0, 0, 2387, 1141, 228, 17, 1, 0, 0, 0, 0, 7269, 4511, 1189, 135, 9, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Gus Wiseman, Nov 01 2018

Keywords

Comments

The multiset density of a multiset partition is the sum of the numbers of distinct vertices in each part minus the number of parts minus the number of vertices.

Examples

			Triangle begins:
     1
     3    0
     6    0    0
    16    1    0    0
    37    3    0    0    0
   105   18    2    0    0    0
   279   68    7    0    0    0    0
   817  293   46    3    0    0    0    0
  2387 1141  228   17    1    0    0    0    0
  7269 4511 1189  135    9    0    0    0    0    0
		

Crossrefs

First column is A321229. Row sums are A007718.

A322111 Number of non-isomorphic self-dual connected multiset partitions of weight n with multiset density -1.

Original entry on oeis.org

1, 1, 1, 2, 2, 5, 5, 13, 13, 37, 37
Offset: 0

Views

Author

Gus Wiseman, Nov 26 2018

Keywords

Comments

The multiset density of a multiset partition is the sum of the numbers of distinct vertices in each part minus the number of parts minus the number of vertices.
The dual of a multiset partition has, for each vertex, one part consisting of the indices (or positions) of the parts containing that vertex, counted with multiplicity. For example, the dual of {{1,2},{2,2}} is {{1},{1,2,2}}. A multiset partition is self-dual if it is isomorphic to its dual. For example, {{1,1},{1,2,2},{2,3,3}} is self-dual, as it is isomorphic to its dual {{1,1,2},{2,2,3},{3,3}}.
The weight of a multiset partition is the sum of sizes of its parts. Weight is generally not the same as number of vertices.

Examples

			Non-isomorphic representatives of the a(1) = 1 through a(8) = 13 multiset partitions:
  {{1}}                    {{1,1}}
.
  {{1,1,1}}                {{1,1,1,1}}
  {{2},{1,2}}              {{2},{1,2,2}}
.
  {{1,1,1,1,1}}            {{1,1,1,1,1,1}}
  {{1,1},{1,2,2}}          {{2},{1,2,2,2,2}}
  {{2},{1,2,2,2}}          {{2,2},{1,1,2,2}}
  {{2},{1,3},{2,3}}        {{2},{1,3},{2,3,3}}
  {{3},{3},{1,2,3}}        {{3},{3},{1,2,3,3}}
.
  {{1,1,1,1,1,1,1}}        {{1,1,1,1,1,1,1,1}}
  {{1,1,1},{1,2,2,2}}      {{1,1,1},{1,1,2,2,2}}
  {{2},{1,2,2,2,2,2}}      {{2},{1,2,2,2,2,2,2}}
  {{2,2},{1,1,2,2,2}}      {{2,2},{1,1,2,2,2,2}}
  {{1,1},{1,2},{2,3,3}}    {{1,1},{1,2,2},{2,3,3}}
  {{2},{1,3},{2,3,3,3}}    {{2},{1,3},{2,3,3,3,3}}
  {{2},{2,2},{1,2,3,3}}    {{2},{1,3,3},{2,2,3,3}}
  {{3},{1,2,2},{2,3,3}}    {{3},{3},{1,2,3,3,3,3}}
  {{3},{3},{1,2,3,3,3}}    {{3},{3,3},{1,2,2,3,3}}
  {{1},{1},{1,4},{2,3,4}}  {{2},{1,3},{2,4},{3,4,4}}
  {{2},{1,3},{2,4},{3,4}}  {{3},{3},{1,2,4},{3,4,4}}
  {{3},{4},{1,4},{2,3,4}}  {{3},{4},{1,4},{2,3,4,4}}
  {{4},{4},{4},{1,2,3,4}}  {{4},{4},{4},{1,2,3,4,4}}
		

Crossrefs

A322112 Number of non-isomorphic self-dual connected multiset partitions of weight n with no singletons and multiset density -1.

Original entry on oeis.org

1, 0, 1, 1, 1, 2, 2, 4, 4, 9, 9
Offset: 0

Views

Author

Gus Wiseman, Nov 26 2018

Keywords

Comments

The multiset density of a multiset partition is the sum of the numbers of distinct vertices in each part minus the number of parts minus the number of vertices.
The dual of a multiset partition has, for each vertex, one part consisting of the indices (or positions) of the parts containing that vertex, counted with multiplicity. For example, the dual of {{1,2},{2,2}} is {{1},{1,2,2}}. A multiset partition is self-dual if it is isomorphic to its dual. For example, {{1,1},{1,2,2},{2,3,3}} is self-dual, as it is isomorphic to its dual {{1,1,2},{2,2,3},{3,3}}.
The weight of a multiset partition is the sum of sizes of its parts. Weight is generally not the same as number of vertices.

Examples

			Non-isomorphic representatives of the a(2) = 1 through a(10) = 9 multiset partitions:
  {{11}}  {{111}}  {{1111}}  {{11111}}    {{111111}}    {{1111111}}
                             {{11}{122}}  {{22}{1122}}  {{111}{1222}}
                                                        {{22}{11222}}
                                                        {{11}{12}{233}}
.
  {{11111111}}      {{111111111}}        {{1111111111}}
  {{111}{11222}}    {{1111}{12222}}      {{1111}{112222}}
  {{22}{112222}}    {{22}{1122222}}      {{22}{11222222}}
  {{11}{122}{233}}  {{222}{111222}}      {{222}{1112222}}
                    {{11}{11}{12233}}    {{111}{122}{2333}}
                    {{11}{113}{2233}}    {{22}{113}{23333}}
                    {{12}{111}{2333}}    {{22}{1133}{2233}}
                    {{22}{113}{2333}}    {{33}{33}{112233}}
                    {{12}{13}{22}{344}}  {{11}{14}{223}{344}}
		

Crossrefs

Showing 1-3 of 3 results.