It is known that the sum of the first n terms of an is Sn and satisfies Sn = 3 ^ n + K (1) find the value of K and the general formula of sequence an 2) If the sequence BN satisfies a (n + 1) / 2 = (4 + k) ^ anbn, find the first n terms and TN of the sequence BN

It is known that the sum of the first n terms of an is Sn and satisfies Sn = 3 ^ n + K (1) find the value of K and the general formula of sequence an 2) If the sequence BN satisfies a (n + 1) / 2 = (4 + k) ^ anbn, find the first n terms and TN of the sequence BN

(1) An = SN-S (n-1) = 3 ^ n + K-3 ^ (n-1) - k = 3 ^ n-3 ^ n / 3 = 2 * 3 ^ n / 3A1 = S12 = 3 + KK = - 1 (2) a (n + 1) / 2 = [2 * 3 ^ (n + 1) / 3] / 2 = 3 ^ n (4 + k) ^ anbn = 3 ^ (anbn) anbn = n (2 * 3 ^ n) / 3 * BN = NbN = 3N / (2 * 3 ^ n) = 3 / 2 * (n / 3 ^ n),