In the known sequence {an}, A2 = 32, a8 = 1 / 2, an + 1 < an Let TN = ㏒ 2 (A1) + ㏒ 2 (A2) + ····· + ㏒ 2 (an), find the maximum value of TN and the corresponding n value

In the known sequence {an}, A2 = 32, a8 = 1 / 2, an + 1 < an Let TN = ㏒ 2 (A1) + ㏒ 2 (A2) + ····· + ㏒ 2 (an), find the maximum value of TN and the corresponding n value

The common ratio is 1 / 2
The sixth power of Q is A8 / A2
an=64*(1/2) ^n-1
Let the general term of tn be BN
bn=7-n
Tn=7n-n*(n+1)/2
To get TN up to 7-N > = 0
So when n = 6 or n = 7, we get the maximum
Then TN = 21