Recitation 10 Solution 3 32 ()(C) n+1Recitation 10 3 Solution. � � �n �m �n �m 3 i + j = 3 i · 3 j i=0 j=0 i=0 � j=0 � � � �m �n = 3 j · 3 i j=0 i=0 = � 3 m+1 − 1 2 � · � 3 n+1 − 1 2 �