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A325869 Number of maximal subsets of {1..n} containing n such that every pair of distinct elements has a different quotient. 9
1, 1, 1, 2, 3, 4, 6, 6, 6, 20, 32, 29, 57, 83, 113, 183, 373, 233, 549, 360 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..20.

EXAMPLE

The a(1) = 1 through a(7) = 6 subsets:

  {1}  {1,2}  {1,2,3}  {1,3,4}  {1,2,3,5}  {1,2,5,6}    {1,2,3,5,7}

                       {2,3,4}  {1,3,4,5}  {2,3,5,6}    {1,2,5,6,7}

                                {2,3,4,5}  {2,4,5,6}    {2,3,4,5,7}

                                           {1,3,4,5,6}  {2,3,5,6,7}

                                                        {2,4,5,6,7}

                                                        {1,3,4,5,6,7}

MATHEMATICA

fasmax[y_]:=Complement[y, Union@@(Most[Subsets[#]]&)/@y];

Table[Length[fasmax[Select[Subsets[Range[n]], MemberQ[#, n]&&UnsameQ@@Divide@@@Subsets[#, {2}]&]]], {n, 10}]

CROSSREFS

Cf. A025582, A067992, A108917, A143823, A196723, A196724.

Cf. A325853, A325854, A325858, A325860, A325861, A325864, A325868.

Sequence in context: A240809 A214322 A075527 * A154257 A297351 A060019

Adjacent sequences:  A325866 A325867 A325868 * A325870 A325871 A325872

KEYWORD

nonn,more

AUTHOR

Gus Wiseman, Jun 02 2019

STATUS

approved

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Last modified August 9 13:57 EDT 2020. Contains 336323 sequences. (Running on oeis4.)