first off, is there a such thing as a random access random number generator, where you could not only sequentially generate random numbers as we're all used to, assuming rand100() always generates a value from 0-100:

for (int i=0;i<5;i++)
   print rand100()

output: 
14
75
36
22
67

but also randomly access any random value like:

rand100(0) would output 14 as long as you didn't change the seed

rand100(3) would always output 22

rand100(4) would always output 67

and so on...

I've actually found an open-source generator algorithm that does this, but you cannot change the seed. I know that pseudorandomness is a complex field; I wouldn't know how to alter it to add that functionality.

Is there a seedable random access random number generator, preferably open source? or is there a better term for this I can google for more information?

if not, part 2 of my question would be, is there any reliably random open source conventional seedable pseudorandom number generator so I could port it to multiple platforms/languages while retaining a consistent sequence of values for each platform for any given seed?