Recently, I've been introduced to the Bernoullis' Numbers... Whereas really perplexed and complicated. To me it's like a formula and a theory for numbers larger than length of 15! Which I really don't know what the use of this theory for. Can anyone explain it to me? Thanks.

Code:
S0(n)=n
S1(n)=(1/2n)^2-(1/2)n
...............