how to multiply the previous number down a column in an array numpy

I need to create an array without using for loops. Pretty much what I am trying to do is make it so it multiplies a given number by an element in another array, then uses that output to multiply it by the next element in the other array. So if the number is 100 it would multiply it by 2 which comes from the second array, then uses that output(100*2) to multiply it to the second element in the other array and so on and so on.