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 A096827 Number of antichains in divisor lattice D(n). 23
 2, 3, 3, 4, 3, 6, 3, 5, 4, 6, 3, 10, 3, 6, 6, 6, 3, 10, 3, 10, 6, 6, 3, 15, 4, 6, 5, 10, 3, 20, 3, 7, 6, 6, 6, 20, 3, 6, 6, 15, 3, 20, 3, 10, 10, 6, 3, 21, 4, 10, 6, 10, 3, 15, 6, 15, 6, 6, 3, 50, 3, 6, 10, 8, 6, 20, 3, 10, 6, 20, 3, 35, 3, 6, 10, 10, 6, 20, 3, 21, 6, 6, 3, 50, 6, 6, 6, 15, 3, 50, 6 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The divisor lattice D(n) is the lattice of the divisors of the natural number n. The empty set is counted as an antichain in D(n). a(n) = gamma(n+1) where gamma is degree of cardinal completeness of Łukasiewicz n-valued logic. - Artur Jasinski, Mar 01 2010 REFERENCES Alexander S. Karpenko, Lukasiewicz's Logics and Prime Numbers, Luniver Press, Beckington, 2006. See Table I p. 113. LINKS Arkadiusz Wesolowski, Table of n, a(n) for n = 1..990 FORMULA a(n) = A285573(n) + 1. - Gus Wiseman, Aug 24 2018 MATHEMATICA nn=200; stableSets[u_, Q_]:=If[Length[u]===0, {{}}, With[{w=First[u]}, Join[stableSets[DeleteCases[u, w], Q], Prepend[#, w]&/@stableSets[DeleteCases[u, r_/; r===w||Q[r, w]||Q[w, r]], Q]]]]; Table[Length[stableSets[Divisors[n], Divisible]], {n, nn}] (* Gus Wiseman, Aug 24 2018 *) CROSSREFS Cf. A096825, A096826, A097699. Cf. A175177, A175178. - Artur Jasinski, Mar 01 2010 Cf. A000005, A008480, A253249, A285572 A285573. Sequence in context: A186971 A329255 A262535 * A298321 A226142 A063826 Adjacent sequences: A096824 A096825 A096826 * A096828 A096829 A096830 KEYWORD nonn AUTHOR Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 17 2004 EXTENSIONS More terms from John W. Layman, Aug 20 2004 STATUS approved

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Last modified December 3 16:35 EST 2022. Contains 358534 sequences. (Running on oeis4.)