W = {(VM + D) + (Y + [Y/4] + VC – a)}7
where:
W = Weekday (see Day of Week Table)
VM = Value for Month from Month Table*
D = Day
Y = Last two digits of the Year
[n] = Integer of n rounding down
VC = Value of Century from Century Table*
a = (adjustment) Subtract 1 for date in leap year if Month is January or February, but not in ’00 years where Y/400 ≠ [Y/400]
{n}7 = Base 7. Reduce number (n) by largest multiple of 7 in it to a number between 0 and 6.
* The Month and Century tables here and in the technique itself could be distilled further to formulas but eventually there would have to be a table for the Months (i.e., the number of days in a month since they are random). Besides, that more basic Month formula and the formula for computing the raw Century values would make the technique so complex that no one would be able to master it or do it quickly. As it is now, the technique is a Goldilock's technique, just the right balance among mathematics, tables and process.
* The Month and Century tables here and in the technique itself could be distilled further to formulas but eventually there would have to be a table for the Months (i.e., the number of days in a month since they are random). Besides, that more basic Month formula and the formula for computing the raw Century values would make the technique so complex that no one would be able to master it or do it quickly. As it is now, the technique is a Goldilock's technique, just the right balance among mathematics, tables and process.
