40 division one winners and unusual numbers: Was Wednesday NZ's most peculiar Lotto draw?

Lotto's Wednesday night draw with its record 40 division one winners surely ranks as one of the most peculiar yet.

Imagine overcoming odds of 1 in 3.8 million to pick all six winning numbers only to find you have to share the prize with 40 others.

It meant each of the 40 winners took home just a $25,000 share of the prize and will perhaps be remembered as the most unlucky winners in the lottery's 30-year history.

Although, to be fair, two of the 40 also won an additional $2.5m for picking the Powerball number.

Yet it wasn't just the sheer number of winners that marked the draw out as unusual.

The winning numbers - 3, 5, 7, 9, 11 and 13 - were also unusual because they were all low and followed a "pleasing" pattern.

This occurrence - in which every number was below 14 - has just a 1 in 2000 chance of happening, University of Auckland associate professor in statistics Russell Millar says.

Yet despite being rare, the low numbers and patterns also likely played a big part in why there were so many winners, Millar said.

That was because some Lotto players regularly pick low numbers that relate to the dates of the birthdays or anniversaries of their loved ones, he said.

Others like to pick numbers according to pleasing patterns, such as the 3, 5, 7, 9, 11 and 13, in Wednesday's draw.

It means that while Wednesday's numbers were a rare anomaly, they were more favourable to the preferences of human Lotto players.

By contrast, if every ticket had been randomly generated by a computer then there would have been next-to-no chance of 40 people winning first division.

Millar said the odds of 40 people winning Wednesday night's numbers from randomly generated tickets was 0.000000000000000000000000000000000001.

That's 35 zeroes behind the decimal point and "it is not going to happen", Millar said.

Another strange twist from Wednesday's draw was that one Hawke's Bay shop on the outskirts of Hastings sold four division one winning tickets.

Millar said those tickets most likely belonged to one or two people rather than four separate winners.

In other words, one person likely chose the same six division one numbers on each ticket but alternated them with a different Powerball number.

He said it was so unlikely that a computer in one shop could randomly generate four division one winning tickets in the same draw that the sun was more likely to transform into a "red dwarf" star before it happened.

While the odds of somebody winning Lotto each week are relatively high, an individual person's remain very low at a 1 in 3.8m chance.

Millar said one way to picture these odds was to imagine 3.8m Lotto tickets being printed - one for every possible set of winning numbers.

This stack would then stand as tall as Auckland's Sky Tower and the winner would have to pick the winning ticket out from the stack.

Despite knowing the size of the odds stacked against him better than most, Millar said he has bought Lotto tickets once before "but, of course, I should have bought a bottle of wine instead".

However, he said a person's best hope of winning is to use randomly generated numbers and to avoid predictable patterns or a narrow range of numbers.

University of Canterbury associate professor and head of the Statistics Consulting Unit Elena Moltchanova said that as a statistician she never plays Lotto.

But she does have a tip. Because many people use low numbers, she said it's better to use high numbers.

This might give you a better chance of winning, but it does mean that if you are lucky enough to win you are less likely to have to share your prize with 40 others.