11 Mar
2005
11 Mar
'05
3:40 p.m.
Wouter Meeussen writes: << of all subsets of the n-th roots of -1, n= 1 to 20, how many add to zero? ?? 0, 1, 1, 3, 1, 6, 1, 11, 4, 8, 1, 50, 1, 10, 9, 107, 1, 240, 1, 316 ?? where are the 'groupies' when you need them?
It appears you have 6 subsets of the 6th roots of unity, but I count 9 subsets (03, 14, 25, 024, 135, 0134, 2350, 3401, 012345). (In any case there could be another sequence based only on minimal such subsets,but it wouldn't be as interesting.) --Dan