364

 “More than any astronomical aspect, the 364-day year is characterized by its numerical harmony. In fact the best definition for the year is neither a ‘solar’ nor ‘luni-solar’ year but rather a seven-based (septenary) schematic year. This definition gives the best account for most manifestations of this sectarian reckoning. The year ideally begins in the spring equinox. It is divided symmetrically into a hierarchical order of time periods, the hierarchical dimension emphasized quite strongly in the textual sources (1 En 82:9–20; Jub 6:29–31; 4Q328, 4Q329). The sources underline the division of the year into 52 weeks and hence into 4 quarters of 13 weeks or 91 days each. The quarters are sometimes designated by the term tequfah, ‘season, period’ or maybe more accurately ‘solstice, equinox’.”

“The fourfold division of the year, most probably borrowed from the Mesopotamian pattern, was well absorbed in Jewish tradition, as it is attested not only in the sectarian 364-day calendar tradition but also in later rabbinic texts and mosaics from the late Roman period. The tequfot are marked by the sun’s cardinal points, with each solstice and equinox date standing at the conclusion, or sometimes at the beginning of every quarter. These four added days (sometimes called ‘epagomenal’ days after the practice of the Egyptian civil year), one in each quarter, constitute the difference between the ideal year of 360 days and the distinctive 364-day year. The emphasis on solar movements and the seasons of the year, at least in the ideal level, is an important characteristic of the 364-day calendar tradition.”

― Jonathan Ben-Dov, The 364-Day Year in the Dead Sea Scrolls and Jewish Pseudepigrapha

Commentary: 91 ÷ 7 = 13
7 days in a week, 13 weeks (91 days) in a tekufot, and 4 tefukot in a year of 364 days.

91 is the 13th triangular number.

364 is the 12th tetrahedral number.

3+6+4 = 13

13 is also the 2nd star number, and the star it specifically makes is the 'Star of David'... the most famous example of that being on the Great Seal of the United States, which is 13 individual stars composing the main star shape.