Limerick
(12+144+20 + 3 4**(1/2))/7 + 5*11 = 9**2 + 0
A dozen, a gross, and a score,
Plus three times the square root of four,
Divided by seven
Plus five times eleven
Is nine squared and naught a bit more.
I'm trying to relate this limerick to calendrics.
The first sum works out to 182, which is half a year.
Dividing by seven gives number of weeks in 1/2 year.
I'm not yet sure what to do about the rest. Anyway, thinking
about this has got me starting to think of a calendar related
item for as many integers as possible, along these lines:
2: days in a weekend
3: Maximum number of Friday the 13ths in a year.
4: quarters in a year
4: solstices and equinoxes in a year
4: number of principal phases of the moon
5: days in a work week
5: days at the end of the Egyption calendar and Mayan Haab not belonging to a month
6: Jubilees in 293 solar years
7: days in a week
8: years in an Octaetris
8: days in Roman market day cycle
10: days in the Egyptian and French Republican "week" (decade)
11: years after which Easter is ofter the same
12: months in Julian/Gregorian calendar year
12: lunar months in a Islamic year
12: animals in the Chinese zodiac
13: months in calendar year with 28 day months
13: lunar months in a lunisolar long year
13: weeks in a quarter
14: days in two weeks (fortnight)
14: lunar months in a full moon cycle (approx)
14: different calendars in Julian, Gregorian, Hebrew calendars, taking account of weekdays
15: lunar months in a short yerm
15: years in Roman cycle of indication (tax collection)
16: full moon cycles in a Saros
17: lunar months in a full yerm
19: years in a Metonic cycle
19: days in a Bahai month and Bahai months in a year
20: base of Mayan counting system
28: years in a Julian cycle with days of week
28: days in month of 13 month calendar
28: days in February in a common year
29: days in February in a leap year
29: days in a short lunar month
30: days in a long lunar month
30: days in April, June, September or November
30: The number of years in a cycle of the Tabular Islamic Calendar
31: days in any other Gregorian or Julian month
33: years of 365 days plus 8 leap days have a mean length of 365.242424.. days
35: Number of different possible dates for Easter (from March 22 to April 25)
38: eclipse seasons in a Saros
38: weeks in approximately 9 lunar months.
48: Number of Friday the 13ths in a 28-year Julian cycle
49: 364-day years in a Jubilee
49: lunar months reckoned to be 1447 days
52: weeks in a year (approx)
55: weeks in an abundant long lunisolar year
59: Usually, the number of days in two consecutive lunar calendar months
60: Base of the Babylonian counting system, which survives in our minutes and seconds.
61: eclipse seasons in an Inex
62: years with 15 leap days has a whole number of weeks and of 5-day cycles. The mean year is 365.241935... days.
70: years fir siderial year to fall one day behind tropical year (approx)
73: days in 1/5 year (approx)
73: days in 1/8 Venus synodic period (approx)
91: days in a quarter (approx)
99: lunar months in an Octaetris
128: years a Julian leap day is skipped would produce a mean year of 365.2421875 days
153: number of days in 5 consecutive Julian/Gregorian months not containing February
183: number of 49-month cycles in 725 years
210: days in an Indonesian cycle of integer numbers of 5, 6, and 7-day cycles
223: lunar months in a Saros
235: lunar months in a Metonic cycle
243: number of years in Venus transit rhythm
258: number of centuries in a cycle of the precession of equinoxes (approx)
260: days in a Mayan Tzolkin
293: solar years in six jubilees
294: years of 364 days is very close to 293 solar years
334: years reckoned to be 4131 lunar months
353: years reckoned to be 4366 lunar months
353: days in a deficient short lunisolar year
354: days in a regular short lunisolar year
355: days in a abundant short lunisolar year
358: lunar months in an Inex
364: days in 52 weeks
365: days in a solar common year
365: days of a leapday calendar, Egyptian calendar, Mayan Haab cycle
366: days in a solar leap year
371: days in a leapweek year
383: days in a deficient long lunisolar year
384: days in a regular long lunisolar year
385: days in a abundant long lunisolar year (exactly 55 weeks)
391: years reckoned to be 403 lunar years
and also 824 eclipse seasons (Palmen cycle)
400: years in a Gregorian leap cycle
443: days in a short yerm
502: days in a full yerm
532: years in a Julian Easter cycle
584: days in a synodic period of Venus (approx)
649: shortest accurate lunisolar cycle
688: Friday 13ths in a 400 year Gregorian cycle
725: years in 183 49-month cycles
793: number of 1080th of an hour that the mean Hebrew month exceeds 29 days 12 hours.
850: lunar months in a 52-yerm cycle
896: years in the cycle of Bonavian Civil calendar (=7*128)
945: days in a week of weeks
945: days in 32 synodic months (approx)
945: days in 31 Gregorian months (frequently)
1004: days in 34 synodic months (approx)
1004: days in 33 Gregorian months (frequently)
1447: days in a 49-month cycle (lunar)
1461: days in 4 Julian years including a leap year
1507: days should have 1 leap day to match Vernal Equinox year length
1508: days should have 1 leap day to match ? year length
2835: days in a Windu cycle of 96 lunar months (3*945)
2894: days (twice 1447) in 98 synodic months (approx) and 28 days short of 8 Julian years
4131: lunar months in 334-year cycle
4366: lunar months in 353-year cycle
6300: years before New Eastern Orthodox calendar repeats
6686: Martian days in a Martian 10-year cycle
6939: days in a Metonic cycle (approx)
6940: days in a Metonic cycle (approx)
10631: days in a Tabular Islamic 30-year cycle
12053: days in a 33-year cycle with 8 leap years
17836: days in a Jubilee (49 364-day years)
18980: days in a Mayan calendar round
20871: weeks in a Gregorian 400-year cycle
25101: days in a 52-yerm cycle
27759: days in a Callypic 76-year cycle
107016: days in six jubilee cycle (294 364-day years)
121991: days in 334-year cycle (approx)
146097: days in a Gregorian 400-year cycle
1872000: days in one cycle of Mayan long count
etc.
The goal is to have something for as many numbers as possible.
If you'd like to add entries yourself, feel free to upload an
amended version of this file. -- Victor Engel
I've added many. Karl Palmen 2002-08-07
Additions paraphrased from Karl's email post of 2002-01-31 referencing Sepp's calendar numbers
Copyright by Contributors (alphabetized by last name):
Victor Engel
Jean Fontaine
Clarence Kelogg
Karl Palmen
Sepp Rothwangl
Amos Shapir