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The sequence N of natural numbers is divided into classes as follows: 1 2 3 4 5 6 7 8 9 10 11 12 … … … … … … …… …… …… …… …… …… Show that the sum of the numbers in nth row is n (2n2 + 1).

The sequence N of natural numbers is divided into classes as follows: 1 2 3 4 5 6 7 8 9 10 11 12 … … … … … … …… …… …… …… …… …… Show that the sum of the numbers in nth row is n (2n2 + 1).