A319792 Number of non-isomorphic connected set systems of weight n with empty intersection.
1, 0, 0, 0, 1, 2, 9, 22, 69, 190, 567, 1640, 5025, 15404, 49048, 159074, 531165, 1813627, 6352739, 22759620, 83443086, 312612543, 1196356133, 4672620842, 18615188819, 75593464871, 312729620542, 1317267618429, 5646454341658, 24618309943464, 109123789229297
Offset: 0
Keywords
Examples
Non-isomorphic representatives of the a(4) = 1 through a(6) = 9 connected set systems: 4: {{1},{2},{1,2}} 5: {{2},{3},{1,2,3}} {{2},{1,3},{2,3}} 6: {{1},{1,4},{2,3,4}} {{1},{2,3},{1,2,3}} {{3},{4},{1,2,3,4}} {{3},{1,4},{2,3,4}} {{1,2},{1,3},{2,3}} {{1,3},{2,4},{3,4}} {{1},{2},{3},{1,2,3}} {{1},{2},{1,3},{2,3}} {{2},{3},{1,3},{2,3}}
Links
- Andrew Howroyd, Table of n, a(n) for n = 0..50
Crossrefs
Formula
Extensions
Terms a(11) and beyond from Andrew Howroyd, May 31 2023
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