Question

How many collections of six positive, odd integers have a sum of 18? Note that 1 + 1 + 1 + 3 + 3 + 9 and 9 + 1 + 3 + 1 + 3 + 1 are considered to be the same collection.

Answer 1

11

Explanation:

Suitable software can generate these collections. They are ...

{13,1,1,1,1,1}, {11,3,1,1,1,1}, {9,5,1,1,1,1}, {9,3,3,1,1,1},

{7,7,1,1,1,1}, {7,5,3,1,1,1}, {7,3,3,3,1,1}, {5,5,5,1,1,1},

{5,5,3,3,1,1}, {5,3,3,3,3,1}, {3,3,3,3,3,3}}