There seems to be an error in the sequence. However, the result is the same in both cases:
$\text{len}(a_{n})$ is the length of $a_{n}$ in English (only letters)
$a_n = \text{len}(a_{n-1}) \times \text{len}(a_{n-2})$
0 = 0 * 0 $\rightarrow$ length of "zero" is 4
0 = 4 * 0 $\rightarrow$ length of "zero" is 4
16 = 4 * 4 $\rightarrow$ length of "sixteen" is 7
28 = 7 * 4 $\rightarrow$ length of "twenty eight" is 11
77 = 11 * 7 $\rightarrow$ length of "seventy seven" is 12
Here we have a mistake (or some additional rule that requires you to change from 11 to 12):
144 = 12 * 12 $\rightarrow$ length of "one hundred and forty four" is 22
But for the correct value we get the same result:
132 = 12 * 11 $\rightarrow$ length of "one hundred and thirty two" is 22
264 = 22 * 12 $\rightarrow$ length of "two hundred and sixty four" is 22
484 = 22 * 22 $\rightarrow$ that's the final answer