Lottery officials say no ticket has matched all six Powerball numbers.  That means the record $949.8 million jackpot is expected to soar to $1.3 billion for Wednesday's drawing.

The jackpot started out Nov. 4 at $40 million and has rolled over 18 times.  The latest jackpot estimate of $1.3 billion would be twice as large as the previous biggest U.S. lottery prize from March 30, 2012, when Mega Millions paid $656 million for three tickets from Kansas, Illinois and Maryland.

The chances of picking the right combination of numbers is like flipping a coin and getting heads 28 times in a row, according to Jeffrey Miecznikowski, an associate professor of biostatistics at the University at Buffalo in New York.