in reply to (homework) Find Series from list of integers
So you have a sequence that may or may not be the numbers you show. You want a formula. Heard of graphs? You have an even number so they are not (all) primes. Even the simplest analysis of this sequence:
8168300941723 0 8203756951684 -35456009961 8304283191943 -100526240259 8541534872809 -237251680866 8746833361583 -205298488774
yields important information. ie it is not a linear sequence, nor is it a pure geometric progression. As you can see it increases by 3.5e10 1.0e11 2.3e11 BUT then only 2.0e11.