Question

What is the mathematical basis for those Random Number Generators?

Answer 1

which are not truly 'random', but pseudorandom

Answer 2

Depends on the random number generator in question.

Answer 3

like the C standard library's rand() function

Answer 4

They all use a "seed", which biases the randomness.

Answer 5

but after that, how are the numbers themselves generated? is it like an equation?

Answer 6

Relevant quote: "Any one who considers arithmetical methods of producing random digits is, of course, in a state of sin." -- John Von Neumann

Answer 7

Yes, it is a set of equations. Each time, the seed changes, so the next time, you get a different number. Again, it is not quite random. But, serves some purposes.

Answer 8

is it possible to predict it if it depends on time? why not?