A272699 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

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.

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

EXAMPLE

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

CROSSREFS

Cf. A057349, A057350.

Sequence in context: A266262 A105387 A011232 * A138344 A354633 A171037

Adjacent sequences: A272696 A272697 A272698 * A272700 A272701 A272702

KEYWORD

nonn

AUTHOR

Nathan Fox, May 04 2016

STATUS

approved