Thanks for the Kata!

I got confused because you say first and last digit when you mean "first (most significant)" and "last (least significant)" digit.

The sample test for python does not work. I replaced expect_equals with assert_equals and it needed an extra space in the answer.
This lead me to believe the submit was broken but it was my code.

Funny how nobody got a vote for best practices. That just indicates how hard it is.

The severs must be getting over loaded. I had to submit my solution a bunch of times before it passed without timing out.

When submitting my solution math.log gave me a domain error
Had to resort to awhile loop instead
This katta is more about find the math trick than programing.
Does anyone have a pointer to the math behind this trick?

The test case supplied does not work
There is a trick test case where no arguments are entered.

1.01 returns 'F'
Please add it to the visiable test cases so users don't spend allot of time figuring it out.

Mine wasn't passing the fifth test then suddenly is passed.

Try these numbers
print powerof4(1125899906842624)
print powerof4(1125899906842625)
the first is 4**25, the second should return false.
See my solution.