a(n) = order of the orthogonal group O_n(2) if n is odd or O^(+)_n(2) if n is even.

A028666

a(n) = order of the orthogonal group O_n(2) if n is odd or O^(+)_n(2) if n is even.

Terms

    a(0) =1a(1) =12a(2) =2880a(3) =11612160a(4) =758041804800

External references