
COMMENTS

Every term in this sequence is odd, since 0 is a possible determinant, and if d is a possible determinant then so is d.
a(n) >= 1 + 2^n, since every integer determinant between 2^(n1) and 2^(n1) is possible (see MathOverflow link).


EXAMPLE

For n = 2, the possible determinants of a 2x2 matrix with entries from {1,0,1} are 2, 1, 0, 1, and 2. Since there are 5 numbers in this list, a(2) = 5.
The possible nonnegative determinants for small values of n are as follows (all the negatives of these numbers are also possible determinants):
n = 1: 0, 1
n = 2: 0, 1, 2
n = 3: 0, 1, 2, 3, 4
n = 4: 0 through 10, 12, 16
n = 5: 0 through 28, 30, 32, 36, 40, 48
