In Honor of 13013
The number 13
https://en.wikipedia.org/wiki/Lunar_calendar
https://www.history.com/news/whats-so-unlucky-about-the-number-13
https://en.wikipedia.org/wiki/13_(number)
"13 (thirteen) is the natural number following 12 and preceding 14.
Strikingly folkloric aspects of the number 13 have been noted in various cultures around the world: one theory is that this is due to the cultures employing lunar-solar calendars (there are approximately 12.41 lunations per solar year, and hence 12 "true months" plus a smaller, and often portentous, thirteenth month). This can be witnessed, for example, in the "Twelve Days of Christmas" of Western European tradition.[1]
The number 13 is:
the sixth prime number.
the smallest emirp (a prime that is a different prime when its digits are reversed).[2]
one of only three known Wilson primes.[3]
a Fibonacci number.
a happy number.[4]
the third centered square number.[5]
a lucky number.[6]
equal to the sum of the squares of the digits of its own square in bases 4 and 83
the smallest number whose fourth power can be written as a sum of two consecutive square numbers (1192 + 1202).
Since 52 + 122 = 132, (5, 12, 13) forms a Pythagorean triple.
There are 13 Archimedean solids as normally counted, although some include the Elongated square gyrobicupola as a fourteenth.
A standard torus can be sliced into 13 pieces with just 3 plane cuts.[2]
There are also 13 different ways for the three fastest horses in a horse race to finish, allowing for ties, a fact that can be expressed mathematically by 13 being the third ordered Bell number.[7]"
In languages
Grammar
In all Germanic languages, 13 is the first compound number; the numbers 11 and 12 have their own names.
The Romance languages use different systems: In Italian, 11 is the first compound number (undici), as in Romanian (unsprezece), while in Spanish and Portuguese, the numbers up to and including 15 (Spanish quince, Portuguese quinze), and in French up to and including 16 (seize) have their own names. This is also the case in most Slavic languages, Hindi-Urdu and other South Asian languages.[example needed]
Folklore
In Germany, according to an old tradition, 13 (dreizehn), as the first compound number, was the first number written in digits; the numbers 0 (null) through 12 (zwölf) were spelled out. The Duden (the German standard dictionary) now calls this tradition (which was actually never written down as an official rule) outdated and no longer valid, but many writers still follow it.[8]
In religion
Islam
In Shia Islam, 13 signifies the 13th day of the month of Rajab (the Lunar calendar), which is the birth of Imam Ali. 13 also is a total of 1 Prophet and 12 Imams in the Islamic School of Thought. However, in Sunni Islam, the number 13 bears no symbolic significance.
Christianity
The apparitions of the Virgin of Fátima in 1917 were claimed to occur on the 13th day of six consecutive months.[9]
In Catholic devotional practice, the number thirteen is also associated with Saint Anthony of Padua, since his feast day falls on June 13. A traditional devotion called the Thirteen Tuesdays of St. Anthony[10] involves praying to the saint every Tuesday over a period of thirteen weeks. Another devotion, St. Anthony's Chaplet, consists of thirteen decades of three beads each.[11]
Sikhism
According to famous Sakhi (Evidence) or story of Guru Nanak Dev Ji, when he was an accountant at a town of Sultanpur Lodhi, he was distributing groceries to people. When he gave groceries to the 13th person, he stopped because in Gurmukhi and Hindi the word 13 is called Terah, which means yours. And Guru Nanak Dev Ji kept saying, "Yours, yours, yours…" remembering God. People reported to the emperor that Guru Nanak Dev Ji was giving out free food to the people. When treasures were checked, there was more money than before.
The Vaisakhi, which commemorates the creation of "Khalsa" or pure Sikh was celebrated on April 13 for many years.
Judaism
In Judaism, 13 signifies the age at which a boy matures and becomes a Bar Mitzvah, i.e., a full member of the Jewish faith (counts as a member of Minyan).
The number of principles of Jewish faith according to Maimonides.
According to Rabbinic commentary on the Torah, God has 13 Attributes of Mercy.
Zoroastrianism
Since beginning of the Nowruz tradition, the 13th day of each new Iranian year is called Sizdah Be-dar, a festival dedicated to pranks and spending time outdoors.[12]