Number of labelled graphs. I'm still beginner in mathematic. How to prove this formula with induction or another way. I have: $2^{ n(n-1) /2}$, if , i sum this i have $1+2+8+64+...$ so on. How i can prove its equal to formula? $2^{ n(n-1) /2}$ I get this formula from: how many ways to find labeled graph with $ n$ points. Help me to solve it and can you give me some advise to advance my mathematic thanks

With $n$ labelled vertices, there are $\dfrac{n(n-1)}{2}$ potential edges, each one of which may be present or not, so there are $2^{n(n-1)/2}$ possible different graphs.