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 A304982 Number of unlabeled clutters (connected antichains) spanning up to n vertices with singleton edges allowed. 8
 1, 2, 5, 19, 137, 3053, 822526 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The initial terms 1, 2, 5, 19 are the same as A304981 but the remaining terms differ. LINKS FORMULA Partial sums of A304983. EXAMPLE Non-isomorphic representatives of the a(3) = 19 clutters: {} {{1}} {{1,2}} {{1,2,3}} {{2},{1,2}} {{1,3},{2,3}} {{3},{1,2,3}} {{1},{2},{1,2}} {{1,2},{1,3},{2,3}} {{3},{1,2},{2,3}} {{3},{1,3},{2,3}} {{2},{3},{1,2,3}} {{1},{2},{3},{1,2,3}} {{2},{3},{1,2},{1,3}} {{3},{1,2},{1,3},{2,3}} {{2},{3},{1,3},{2,3}} {{1},{2},{3},{1,3},{2,3}} {{2},{3},{1,2},{1,3},{2,3}} {{1},{2},{3},{1,2},{1,3},{2,3}} CROSSREFS Cf. A048143, A198085, A261006, A304912, A304981, A304982, A304983, A304984, A304985, A304986. Sequence in context: A272906 A054926 A002786 * A039719 A332653 A198203 Adjacent sequences:  A304979 A304980 A304981 * A304983 A304984 A304985 KEYWORD nonn,more AUTHOR Gus Wiseman, May 23 2018 EXTENSIONS a(5)-a(6) from Andrew Howroyd, Aug 14 2019 STATUS approved

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Last modified April 14 18:11 EDT 2021. Contains 342950 sequences. (Running on oeis4.)