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