State Pension forecast vs actual payment

MarlowMallard

molerat said:

There are many places that pay 4 weekly, some of the supermarkets were on that schedule.  I remember a few years back when there was a big fuss at Asda over the tax when getting 14 pay days in a year.  Seems it happens once every 20 years and in 2012-13 it caused Asda staff to owe over £12M in tax.

I checked the once every 20 years: the calendar repeats on a 28-year pattern, and 28 calendar years = (28*52 + 5) weeks  (an extra 35 days from 21 non-leap and 7 leap years).  Now 5 has no common factor with 4, so we need to look at 112 calendar years = (112*52 + 20) weeks, which is (112*13 + 5) blocks of 4 weeks.   So the 14th payday will happen exactly 5 times in 112 consecutive years,  not necessarily equally spaced.  
To be pedantic, this was true in between 1901 to 2099,  but the fact that 2100 won't be a leap year will break it; I have not bothered correcting for this.