S(7, 3) = \frac16 \left( 3^7 - 3 \cdot 2^7 + 3 \cdot 1^7 \right) = \frac16 (2187 - 3 \cdot 128 + 3) = \frac16 (2187 - 384 + 3) = \frac18066 = 301 - Portal da Acústica