is 13 a lucky number in your country, TD? In most countries it counts as an unlucky one.
Reason: 1 messiah + 12 apostles = 13 of which one was a traitor, hence a dinner or meeting with 13 people at a table is considered to be potentially fatal; see also: Agatha Christie: 13 At Dinner [aka: Lord Edgeware Dies]
Indeed, in Christian mythology the number 13 has become one of ill omen But then, Christianity is a new-fangled thing anyway...
There's an old saying, something like: "Neither 7 nor 9
" - 7 is by tradition, a you say, a lucky number and 9 was considered unlucky -it is possible that the expression "7 9 13" might have come from this.
ETA: Fourth wedding of the day taking place in the church across the street from me right now!