On a piano, each key has a frequency, and each subsequent key (black or white) is a known amount higher. Ex: The A key above middle C key has a frequency of 440 Hz. Each subsequent key (black or white) has a frequency of 440 * rⁿ, where n is the number of keys from that A key, and r is 2^(1/12). Given an initial frequency, output that frequency and the next 3 higher key frequencies. If the input is 440, the output is: 440 493.883 523.251 554.365.

Note: Include one statement to compute r = 2^(1/12) using the pow function, then use r in the formula f_n = f₀ * rⁿ. (You'll have three statements using that formula, different only in the value for n).

(Note 4/17/17: A student noticed that our example and test cases are skipping n=1, starting instead with n=2. We won't change the lab right now, so just assume you've been asked for steps n=2, 3, and 4.)