81
243
It is 3 followed by 1
25, 36, 49, 64, 81, 100...
There are at least three possible answers, consistent with the information given in the question. Short of reading the mind of the person who posed the question, there is no way of determining which of these (or other) solutions is the "correct" one. Answer A: It is 81. The sequence is 1 followed by 2 lots of 9^1, then 3 lots of n^2, then 4 lots of n^3, etc. Answer B: It is 729. The sequence is 1 followed by pairs of powers of n. Answer C: It is 6561. The sequence is 1 followed by a pair of 9s, followed by a pair of 9^2, followed by a pair of (9^2)^2, then ((9^2)^2)^2, etc.
81
81
243
243
81 is a single 2-digit number. A single number cannot define a sequence.
81
9, 81, 6561, 43046721, ...This would be the sequence 9^(2^(n-1))
It is 3 followed by 1
3-1-.33 repeating
they are all squares - 1², 2², 5², 6², 7², 9²
81 Each number is 3 x the previous number. So, 3 x 27 = 81.
25 36 49 64 81 100 121 144