Choose possible indexes

Hi Everyone

I'm trying to make an algorithm which gives out possible combination of indexes

for example we have 

0

1

2

3

now I want to have these as groups

{0}

0

{1}

1

{2}

2

{3}

3

{4}

0,1

{5}

0,2

{6}

0,3

{7}

1,2

{8}

1,3

{9}

2,3

{10}

0,1,2

{11}

0,1,3

{12}

0,2,3

{13}

1,2,3

{14}

0,1,2,3

I want it to be parametric so I can have it for any set of indexes

I have tried to solve it with points and then removing duplicate points but it's not helping much

any help is truly appreciated