130976domain: NAppears in sequencesa(n) = 4*8^n - 3*2^n.at n=5A020537a(n) = ChebyshevT(3, n).at n=32A144129Number of 1:2:sqrt(5) proportioned triangles on an (n+1) X (n+1) grid.at n=23A190099Expansion of e.g.f. arcsinh(x*sec(x)) (odd powers only).at n=5A296742