A326020 Number of complete subsets of {1..n}.

1, 2, 3, 4, 6, 9, 15, 27, 50, 95, 185, 365, 724, 1441, 2873, 5735, 11458, 22902, 45789, 91561, 183102, 366180, 732331, 1464626, 2929209, 5858367, 11716674, 23433277, 46866473, 93732852, 187465596, 374931067, 749861989, 1499723808, 2999447418

Offset

0,2

Comments

A set of positive integers summing to n is complete if every nonnegative integer up to n is the sum of some subset.

Links

Charlie Neder, Table of n, a(n) for n = 0..300

Andrzej Kukla and Piotr Miska, On practical sets and A-practical numbers, arXiv:2405.18225 [math.NT], 2024.

Example

The a(0) = 1 through a(6) = 15 subsets:
  {}  {}   {}     {}       {}         {}           {}
      {1}  {1}    {1}      {1}        {1}          {1}
           {1,2}  {1,2}    {1,2}      {1,2}        {1,2}
                  {1,2,3}  {1,2,3}    {1,2,3}      {1,2,3}
                           {1,2,4}    {1,2,4}      {1,2,4}
                           {1,2,3,4}  {1,2,3,4}    {1,2,3,4}
                                      {1,2,3,5}    {1,2,3,5}
                                      {1,2,4,5}    {1,2,3,6}
                                      {1,2,3,4,5}  {1,2,4,5}
                                                   {1,2,4,6}
                                                   {1,2,3,4,5}
                                                   {1,2,3,4,6}
                                                   {1,2,3,5,6}
                                                   {1,2,4,5,6}
                                                   {1,2,3,4,5,6}

Mathematica

Table[Length[Select[Subsets[Range[n]], Union[Plus@@@Subsets[#]]==Range[0, Total[#]]&]], {n, 0, 10}]

Crossrefs

Cf. A002033, A103295, A108917, A126796, A188431, A276024.

Cf. A325684, A325781, A325790, A325791, A325986, A325988, A326016, A326021, A326022, A326036.

Sequence in context: A127604 A268710 A223900 * A192267 A331022 A256774

Adjacent sequences: A326017 A326018 A326019 * A326021 A326022 A326023

Keyword

nonn

Author

Gus Wiseman, Jun 04 2019

Extensions

a(17)-a(34) from Charlie Neder, Jun 05 2019

Status

approved