Monday, March 18, 2013
You know, you might want to check the calendar for March 2002
Okay, I've seen this particular meme multiple times now on GoogleFacePlusBook:
THIS IS THE ONLY TIME WE WILL SEE AND LIVE THIS EVENT
Calendar for March 2013
March 2013 Sun Mon Tue Wed Thr Fri Sat 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 This year March has 5 Fridays, 5 Saturdays and 5 Sundays. This happens once every 823 years. This is called money bags. So, share this to your friends and money will arrive within 4 days. Based on Chinese “Feng Shui.” The one who does not share … will be without money.
The first time I saw it, I thought, Weird—is that true? Really? 823 years since the last time? Okay, let's write some code to answer this—which years has March 1st fallen on a Friday?
#!/usr/bin/env lua
function dayofweek(date)
local a = math.floor((14 - date.month) / 12)
local y = date.year - a
local m = date.month + 12 * a - 2
local d = date.day
+ y
+ math.floor(y / 4)
- math.floor(y / 100)
+ math.floor(y / 400)
+ math.floor(31 * m / 12)
return (d % 7) + 1
end
for year = 1190,2014 do
if dayofweek { year = year , month = 3 , day = 1 } == 6 then
print(year)
end
end
1190 is 823 years ago. Let's see what we get …
1191 1196 1202 1213 1219 1224 1230 1241 1247 1252 1258 1269 1275 1280 1286 1297 1309 1315 1320 1326 1337 1343 1348 1354 1365 1371 1376 1382 1393 1399 1405 1411 1416 1422 1433 1439 1444 1450 1461 1467 1472 1478 1489 1495 1501 1507 1512 1518 1529 1535 1540 1546 1557 1563 1568 1574 1585 1591 1596 1602 1613 1619 1624 1630 1641 1647 1652 1658 1669 1675 1680 1686 1697 1709 1715 1720 1726 1737 1743 1748 1754 1765 1771 1776 1782 1793 1799 1805 1811 1816 1822 1833 1839 1844 1850 1861 1867 1872 1878 1889 1895 1901 1907 1912 1918 1929 1935 1940 1946 1957 1963 1968 1974 1985 1991 1996 2002 2013
(okay, I cleaned up the output a bit)
Well … it's happened 118 times since 1190, and it didn't happen 823 years ago, but 822 years ago, and 817 years ago and … you get the picture.
Hardly a rare occurrence and in thinking about it, any month with 31 days will have three days that happen five times a month (five Sundays, five Mondays and five Tuesdays for instance).
Now, I can hope this puts this particularly medium meme (it's not rare, and it's not well done) out of commission. But alas, I doubt it …
