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.

A305005 Number of labeled clutters (connected antichains) spanning some subset of {1,...,n} without singleton edges.

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%I A305005 #10 Jun 16 2018 13:42:13
%S A305005 1,1,2,9,111,6829,7783192,2414627236071,56130437209370100252463
%N A305005 Number of labeled clutters (connected antichains) spanning some subset of {1,...,n} without singleton edges.
%H A305005 Gus Wiseman, <a href="/A048143/a048143_4.txt">Sequences enumerating clutters, antichains, hypertrees, and hyperforests, organized by labeling, spanning, and allowance of singletons</a>.
%F A305005 Binomial transform of A048143 if we assume A048143(1) = 0.
%F A305005 a(n) = A198085(n) - n + 1. - _Gus Wiseman_, Jun 11 2018
%e A305005 The a(3) = 9 clutters:
%e A305005   {}
%e A305005   {{1,2}}
%e A305005   {{1,3}}
%e A305005   {{2,3}}
%e A305005   {{1,2,3}}
%e A305005   {{1,2},{1,3}}
%e A305005   {{1,2},{2,3}}
%e A305005   {{1,3},{2,3}}
%e A305005   {{1,2},{1,3},{2,3}}
%Y A305005 Cf. A048143, A198085, A261006, A304912, A304981, A304982, A304983, A304984, A304985, A304986.
%K A305005 nonn
%O A305005 0,3
%A A305005 _Gus Wiseman_, May 23 2018