Today is Tuesday. What's the week after the power of 3?

Today is Tuesday. What's the week after the power of 3?

First find out how much power of 3 minus 1 is a multiple of 7
We get 3 ^ 6-1 = 729-1 = 7 * 104
Then 3 ^ 1998-1 = 729 ^ 333-1 = (729-1) (729 ^ 332 + 729 ^ 331 +. + 1) = 7 * 104 *
Is a multiple of 7
That is to say, the power of 3 is a multiple of 7
Three to the power of three is Wednesday