A327591 Number of subsets of {1..n} containing no quotients of pairs of distinct elements.

1, 2, 3, 5, 7, 13, 23, 45, 89, 137, 253, 505, 897, 1793, 3393, 6353, 9721, 19441, 35665, 71329, 129953, 247233, 477665, 955329, 1700417, 2657281, 5184001, 10368001, 19407361, 38814721, 68868353, 137736705, 260693505, 505830401, 999641601, 1882820609, 2807196673

Offset

0,2

Links

Fausto A. C. Cariboni, Table of n, a(n) for n = 0..167, (terms up to a(100) from Peter Kagey based on Andrew Howroyd's b-file for A326489)

Formula

A326489(n) + 1 for n > 0.

Example

The a(0) = 1 through a(5) = 13 subsets:
  {}  {}   {}   {}     {}     {}
      {1}  {1}  {1}    {1}    {1}
           {2}  {2}    {2}    {2}
                {3}    {3}    {3}
                {2,3}  {4}    {4}
                       {2,3}  {5}
                       {3,4}  {2,3}
                              {2,5}
                              {3,4}
                              {3,5}
                              {4,5}
                              {2,3,5}
                              {3,4,5}

Crossrefs

Maximal subsets without quotients are A326492.

Subsets with quotients are A326023.

Subsets without differences or quotients are A326490.

Subsets without products are A326489.

Cf. A007865, A051026, A325860, A325994, A326079, A326117, A326491, A326496.

Sequence in context: A185231 A080190 A076994 * A124147 A227627 A335116

Adjacent sequences: A327588 A327589 A327590 * A327592 A327593 A327594

Keyword

nonn

Author

Peter Kagey, Sep 17 2019

Status

approved