2n 6 4n 7 July 8, 2019 16 32 64 128 4n 9 2n 6 7n 6n 36 6 7 n 1 )=- 2 4n 3 4n 2 7n 6 n 2 n 6 n 7 )- 2 1 4n 34 4n 6 n 2 )=- 24 7n 2 + 4 + 6 + ... + 2n 2 n 6