\\ product of Eisenstein integers prd(u,v) = { (real(u)*real(v) - imag(u)*imag(v)) + (imag(u)*real(v)+real(u)*imag(v)-imag(u)*imag(v))*I; } dz = [0, 1, I, prd(I,I)] a(n) = { my (d=Vecrev(digits(n, #dz)), p=1, z=0); for (k=1, #d, z+=prd(p, dz[1+d[k]]); p*=-2; ); imag(z) } for (n=0, 2^14-1, print (n " " a(n))) quit