Birthday experiment update

OK, so you guessed correctly. The answer is 23. The reason? If you have 3 people together there are 3 possible two person combinations (use your fingers if it helps). If there are 5 people there are 10 possible combinations, 10 people = 25 combinations, 23 people = 253 (see the non-linear growth?). This results in the probability of a match reaching approximately 0.507 (over a 50:50 chance). This can explained much more proficiently by Ivars Peterson than myself.
At the time of posting, only 20 birthdays have been left in the birthday experiment article below and as yet we have not had a match (although we have a suspicious cluster leading up to Xmas eve, and Groms large & small are almost exactly 1 year apart to the day).
If you haven’t left your birthday date in the comments of that article yet then please do… your missing out on unprecedented amounts of fun. Come on…