I can get the first half simply by using the same seed ie 12345 and generating 150 points, however how do i generate the next 150 points such that they are the same as 151-300 points generated in original sequence? what is the seed that i have to provide, is there a way to calculate that seed value?

I don't think you can do that. Your best bet is to use a different seed for every parallel section: generate 150 points on one machine with one seed, and 150 points with a different seed on the second machine.

Warning: Do not use the same seed in different parallel sections! Doing so will duplicate the work done by another machine and the randomness of your results will decrease.

You could alter your sequential program to change seed after 150 generated points. This way, you could achieve reproducibility between sequential and parallel program.