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 A326491 Number of maximal subsets of {1..n} containing no differences or quotients of pairs of distinct elements. 8
 1, 1, 2, 2, 3, 4, 5, 7, 9, 10, 16, 22, 27, 39, 52, 70, 90, 120, 150, 198, 262, 357, 448, 602, 782, 1004, 1294, 1715, 2229, 2932, 3698, 4844, 6259, 8188, 10274, 13446, 16895, 21954, 27470, 35843, 45411 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS FORMULA a(n) = A326497(n) + 1 for n > 1. - Andrew Howroyd, Aug 30 2019 EXAMPLE The a(1) = 1 through a(9) = 10 subsets:   {1}  {1}  {1}    {1}    {1}      {1}      {1}        {1}        {1}        {2}  {2,3}  {2,3}  {2,3}    {2,3}    {2,3,7}    {2,5,6}    {2,6,7}                    {3,4}  {2,5}    {2,5,6}  {2,5,6}    {2,5,8}    {3,4,5}                           {3,4,5}  {3,4,5}  {2,6,7}    {2,6,7}    {3,5,7}                                    {4,5,6}  {3,4,5}    {3,4,5}    {2,3,7,8}                                             {3,5,7}    {3,5,7}    {2,5,6,9}                                             {4,5,6,7}  {2,3,7,8}  {2,5,8,9}                                                        {4,5,6,7}  {4,5,6,7}                                                        {5,6,7,8}  {4,6,7,9}                                                                   {5,6,7,8,9} MATHEMATICA fasmax[y_]:=Complement[y, Union@@(Most[Subsets[#]]&/@y)]; Table[Length[fasmax[Select[Subsets[Range[n]], Intersection[#, Union[Divide@@@Reverse/@Subsets[#, {2}], Subtract@@@Reverse/@Subsets[#, {2}]]]=={}&]]], {n, 0, 10}] CROSSREFS Subsets without differences or quotients are A326490. Subsets with differences and quotients are A326494. Maximal subsets without differences are A121269 Maximal subsets without quotients are A326492. Cf. A007865, A051026, A054519, A326023, A326117, A326489, A326496, A327591. Sequence in context: A152305 A131419 A317177 * A266748 A304883 A280663 Adjacent sequences:  A326488 A326489 A326490 * A326492 A326493 A326494 KEYWORD nonn,more AUTHOR Gus Wiseman, Jul 09 2019 EXTENSIONS a(16)-a(40) from Andrew Howroyd, Aug 30 2019 STATUS approved

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Last modified December 6 22:42 EST 2021. Contains 349567 sequences. (Running on oeis4.)