Welcome to March!
March has multiples of three, in addition to the regular sequence, halfback day, subtraction, and addition days. And get ready for the PI day of the century!
This week is pretty full…
Tuesday 3/3/15 and Friday 3/6/15 have multiples of three for the day, month, and year.
Wednesday is the only day of the year that is a complete sentence – March forth!
Thursday, 3/5/15 is a multiply day – 3 x 5 = 15
Check out this month’s calendar (February 2015). It has one of the rarest configurations you will see. There are exactly four weeks, no spilling over to a fifth week. This only happens in non-leap years when February 1 is on a Sunday; most Februaries are like most other months; they take up five week lines. The next occurrence of only-four-weeks will be in 2026.
The only rarer calendar look is a leap year February. 29 days; the 1st and the 29th are on the same day of the week. The starting day of the week for leap year Februarys rotates once every 28 years. February 1 2016 is on a Monday; it will also be on Monday in 2044. Get ready!
A more common but still unusual month look requires six lines for the weeks. See August 2015. Many calendars get all lazy and double up Sunday and maybe Monday and Tuesday when this occurs. The good honest calendar in the picture gives the six lines we deserve!
This week’s one cool date is next Saturday. 2/28/15 is this month’s half-back day. Go up 26 from 2 to 28, then come halfway back (13) to 15.
Last week featured an Addition Day (2/13/15). This week Tuesday, 2/17/15, is a Minus Subtract Day:
2 – 17 = – 15
Friday this week is a nice Addition day: 2 + 13 = 15.
Every week this month has just one cool date. Last week was a bit fudgy as we tossed in Euler’s Number e. But, just wait until next year, when February will be full of Multiples AND Powers of 2!
This week we honor Euler’s Number, symbolized by the character e. It is the base number for Natural Logarithms. It is an irrational number, which means it cannot be represented by a fraction and its decimal value is unending.
The first several digits of e are 2.7182818284590…
All we need is 2.7 to place e day on February 7.
There is just one cool date this week, a half-back date on 1/29/15. Count up 28 from month one to day 29, then count half-way back, 14, from day 29 to year 15.
Last week there were none, so this week’s one may be an infinite percentage increase? (watch out for dividing by 0!)
There are no recognizably cool dates this week, but we can take the opportunity to look at dates that are sequences. You may know that the century’s last sequence of 1’s occurred last month on 12/13/14. The next one will be 01/02/03 in 2103, OR 02/01/00 if you want to go backwards.
There are still lots of sequences each year; the distance between is larger than 1. When do the other sequences end? There is a nice pattern for sequences up thru 19, since the limiting factor is month 12. Add the number to 12 to get the day of the month, then add the same number to the day to get the year. I listed out the last day for increasing sequences for each; notice that the expiration year increases by two for each number… add it twice sounds like increasing by 2!
After the 19’s, the limiting factor is the last day of the month – 30 or 31. I think the very last sequence day of the century is 1/31/61, a sequence of 30’s. I will check and report back later.
All the sequence dates listed here are increasing… that is , the year is greater than the day is greater than the month, I will also look into decreasing sequences, like 12/11/10. I am afraid they have ended until 2100.
1’s ended in 2014 on 12/13/14
2’s 12/14/16
3’s 12/15/18
4’s 12/16/20
5’s 12/17/22
6’s 12/18/24
7’s 12/19/26
8’s 12/20/28
9’s 12/21/30
10’s 12/22/32
11’s 12/23/34
12’s 12/24/36
13’s 12/25/38
14’s 12/26/40
15’s 12/27/42
16’s 12/28/44
17’s 12/29/46
18’s 12/30/48
19’s 12/31/50
Last one is 30’s on 1/31/61?
Today – 1/15/15 – is a cool number day. 1 and 15 are both powers of 15. 15 to the zeroth power = 1; and 15 to the first power = 15. Please have a power-filled day!
The second full week of the year has several interesting dates, all for different reasons.
Wednesday, 1/14/15, is an addition day, since 1 + 14 = 15
Thursday, 1/15/15, and a multiplication day, since 1 * 15 = 15
Friday, 1/16/15, is a Minus subtract day, since 1 – 16 = -15
And don’t forget that 1/15/15 is also a Reverse Division day since 15 / 1 = 15. This always happens when one of the factors of a multiplication day is 1.
A. Knapp for That 