A272699 Day of the week of Rosh Hashanah in Hebrew year n.

2, 7, 5, 3, 7, 5, 5, 2, 7, 5, 2, 7, 5, 2, 2, 5, 2, 2, 7, 5, 2, 7, 5, 3, 7, 7, 3, 2, 7, 5, 3, 7, 5, 5, 2, 5, 5, 2, 7, 5, 2, 2, 5, 3, 2, 7, 5, 2, 7, 7, 3, 7, 7, 5, 2, 7, 5, 3, 7, 5, 5, 2, 5, 5, 2, 2, 5, 2, 2, 7, 3, 2, 7, 5, 3, 7, 7, 3, 7, 7, 5, 2, 7, 5, 5, 2, 5, 5, 2

Offset: 1

Author

Nathan Fox, May 04 2016

Keywords

• nonn

Comments

Rosh Hashanah, the new year of the Hebrew Calendar, is the first day of the month of Tishri, which typically falls around the September equinox.

The holiday of Rosh Hashanah lasts for two days; this sequence considers only the first day.

The mathematical rules for determining the Hebrew Calendar stipulate that Rosh Hashanah cannot fall on Sunday, Wednesday, or Friday. So, every number in this sequence is 2, 3, 5, or 7.

The Hebrew Calendar is periodic with a period of 689472 years, so this sequence is periodic with period 689472.

Examples

			Rosh Hashanah 5776 fell on Monday, Sep 14 2015, so a(5776)=2.
		

Links

• Nathan Fox, Table of n, a(n) for n = 1..10000
• Wikibooks, Mathematics of the Jewish Calendar.
• D. Zeilberger, Maple program to determine Hebrew dates; Local copy

Crossrefs

Cf. A057349, A057350.