1,2
a(n) <= A086875(n).
For prime power q the number of rank-r n X n matrices over GF(q) is F(r, n) = product j=0..(r-1) (q^n-q^j)^2/(q^r-q^j) so a(n) = sum r=1..n r*product j=0..(r-1) (q^n-q^j)^2/(q^r-q^j) . In this case q=2.
Cf. A086875.
Sequence in context: A193156 A012183 A012230 * A086875 A012211 A036059
Adjacent sequences: A086095 A086096 A086097 * A086099 A086100 A086101
nonn
Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 24 2003
