A014577(n)=1/2*(1+(-1)^(1/2*((n+1)/2^valuation(n+1, 2)-1))) { k=-1; z=0; d=1; for (n=0, 2^24, if (real(z)==0, print (k++ " " imag(z)); ); z += d; d*=if (A014577(n), +I, -I) ) } quit