-8226domain: ZAppears in sequencesProduct_{k>=1} ((1 + x^k)^a(k)) = 1 + 4x.at n=7A038069a(n) = -(1/n) * Sum_{d|n} phi(n/d) * (-4)^d.at n=7A343466Square array A(n,k), n >= 1, k >= 1, read by antidiagonals downwards, where A(n,k) = -(1/n) * Sum_{d|n} phi(n/d) * (-k)^d.at n=62A382993