Examples are $$ Y_{00}=\sqrt{\frac{1}{4\pi}}, $$ for \( l=m_l=0 \), $$ Y_{10}=\sqrt{\frac{3}{4\pi}}cos(\theta), $$ for \( l=1 \) and \( m_l=0 \), $$ Y_{1\pm 1}=\sqrt{\frac{3}{8\pi}}sin(\theta)exp(\pm i\phi), $$ for \( l=1 \) and \( m_l=\pm 1 \), $$ Y_{20}=\sqrt{\frac{5}{16\pi}}(3cos^2(\theta)-1) $$ for \( l=2 \) and \( m_l=0 \) etc.