Those are the numbers that were intended to be broadcast to launch the Nova6 gas on multiple targets in the US. They were implanted in Mason's head by the USSR during his brainwashing while imprisoned at Vorkuta (finish the campaign for more info).
The frequently referenced numbers in 'Lost' were the so called "damned numbers" Hurley used to win the lotto. These were different numbers (4, 8, 15, 16, 23 and 42) & appeared numerous times throughout the series.
MGd00d (on xbox live):
Kino - 41 (2 people)
Five - 30 (4 people)
Nacht - 16 (4 people)
Verruckt - 29 (2 people)
Shi No Numa - 29 (2 people)
Der Riese - 35 (2 people)
Ascension - 39 (4 people)
