[Valandil]

Hmm. Actually, I chose thirteen because
1) it's the sacred number of the horned rat,
2)Let plog(gx) denote the discrete logarithm according to the prime number p, i.e., the number l modulo p − 1 such that
Then 13 is the only prime number p such that for any two primitive roots g and h,
3)Thirteen is the fifth lucky number.
4)The atomic number of aluminium is 13
5)There are 13 zodiac constellations, which consist of the 12 signs in the astrological zodiac and Ophiuchus.
6)The number of participants at the Last Supper was 13
7)In Tarot decks, the #13th card of the Major Arcana is Death.
8)The legion with which Julius Caesar crossed the Rubicon with was the Legio XIII Gemina
9)In egyptian mythos, there are 13 steps between life and death
10)MEtatron's cube is bmade up of 13 circles
11)It's pretty important to the states:
The number of original colonies the United States was founded from. The original flag had thirteen stars, one for each state. New stars have since been added whenever a new state joins the union, but the idea of adding stripes for new states was soon dropped, so the American flag to this day has thirteen horizontal stripes: six white ones and seven red ones.
The Great Seal of the United States has:
13 levels of the truncated pyramid,
13 letters in "E Pluribus Unum", which appears in the banner running through the eagle's beak on the right side of the bill's reverse.
13 letters in the phrase "Annuit Coeptis", which appears over the pyramid on the left side of the bill's reverse.
13 stars above the Eagle,
13 leaves on the olive branch,
13 olives on the olive branch,
13 arrows held by the Eagle, and
13 bars on the shield.
The number of guns in a gun salute to U.S. Army, Air Force and Marine Corps Major Generals, and Navy and Coast Guard Rear Admirals Upper Half.
The Naval Jack of the United States has 13 stripes, 7 red and 6 white, the rattlesnake has 13 buttons on its rattle, and the motto "Don't Tread on Me" has 13 letters
12)There are thirteen steps leading up to the gallows
13)There are thirteen items in this list.

QED