Re: [math-fun] more challenge sequences needed

1) It must be NP-complete 2) It must be simple to describe 3) It should not have been widely explored 4) A solution must be easy to check (= it doesn't require a lot of computation to check) 5) It has to be computed from N=8 to at most 64

this isn't in the database yet, but how about: a(n) = minimum value of k so that k copies each of cubes of sides 1 through n can be used to exactly fill some rectangular box. a(1) = 1 a(2) = 4 a(3) <= 8 a(4) <= 24 a(5) <= 32 and nothing else is known. if they use this, i want to know the answers! the pictures for the same problem for squares in 2 dimensions are nicer, but the values for n=1-17, 19, and 24 are already known. erich