OFFSET
1,3
COMMENTS
Consider the 2^n sums formed from all the subsets of the n-th roots of unity. The number A103314(n) tells how many of these sums are zero. The remaining sums fall into n wedges centered at the origin. The number a(n) gives the number of sums that fall into each wedge. Interestingly, a(n) coincides with A059966(n) when n is either p^k or pq for primes p and q.
LINKS
Max Alekseyev and M. F. Hasler, Table of n, a(n) for n = 1..164
T. D. Noe, Sums of Roots of Unity Plots
FORMULA
a(n) = (2^n - A103314(n))/n.
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, May 25 2005
STATUS
approved