Let be a positive integer such that the number satisfies the following conditions:
It is a perfect 4th power, but not a perfect 16th power, and
The sum of its digits is a prime number less than 10.
Submit your answer as this number.
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Integers that satisfy all three conditions are all powers of four: 4 , 1 6 , 6 4 , 2 5 6 , 1 0 2 4 … . Now, we can calculate whether x is an integer for these values
( x + 1 2 ) 5 = 4 ( x + 1 2 ) 5 = 1 6 ( x + 1 2 ) 5 = 6 4 ( x + 1 2 ) 5 = 2 5 6 ( x + 1 2 ) 5 = 1 0 2 4 ⟹ x = Z ⟹ x = Z ⟹ x = Z ⟹ x = Z ⟹ x = 4
Since we are asked the value of ( x + 1 2 ) 5 for x = 4 . We get the answer as 1 0 2 4