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.

A329128 Number of nonequivalent sets whose translations and reflections cover {1..n}.

Original entry on oeis.org

1, 2, 3, 6, 8, 17, 24, 52, 77, 171, 265, 593, 952, 2131, 3519, 7846, 13238, 29351, 50374, 111031, 193155, 423403, 744616, 1624302, 2881784, 6260030, 11186219, 24213106, 43522800, 93922741, 169653109, 365172178
Offset: 1

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Author

Andrew Howroyd, Nov 07 2019

Keywords

Comments

Equivalence is up to translation and reflection. Only translations and reflections that are subsets of {1..n} are included.

Examples

			For n = 4 there are 6 sets (up to equivalence) that with their reflections and translations cover {1..4}:
  {{1}, {2}, {3}, {4}};
  {{1, 2}, {2, 3}, {3, 4}};
  {{1, 3}, {2, 4}};
  {{1, 2, 4}, {1, 3, 4}};
  {{1, 2, 3}, {2, 3, 4}};
  {{1, 2, 3, 4}}.
.
For n = 5 there are 8 sets (up to equivalence) that with their reflections and translations cover {1..5}:
  {{1}, {2}, {3}, {4}, {5}};
  {{1, 2}, {2, 3}, {3, 4}, {4, 5}};
  {{1, 3}, {2, 4}, {3, 5}};
  {{1, 2, 4}, {1, 3, 4}, {2, 3, 5}, {2, 4, 5}};
  {{1, 2, 3}, {2, 3, 4}, {3, 4, 5}};
  {{1, 2, 3, 5}, {1, 3, 4, 5}};
  {{1, 2, 3, 4}, {2, 3, 4, 5}};
  {{1, 2, 3, 4, 5}}.
		

Crossrefs

Cf. A079500 (if only translations allowed).