“169 (number)”的意思、由来-开放百科全书

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169 (number)

释义

In mathematics
In astronomy
In geography
In the military
In transportation
In TV and radio
In other fields
See also
External links
References

169 (one hundred [and] sixty-nine) is the natural number following 168 and preceding 170.

In mathematics

169 is an odd number, a composite number, and a deficient number.

169 is a square number: 13 x 13 = 169, and if each number is reversed the equation is still true: 31 x 31 = 961. 144 shares this property: 12 x 12 = 144, 21 x 21 = 441.

169 is one of the few squares to also be a centered hexagonal number.^[1] Like all odd squares, it is a centered octagonal number. 169 is an odd-indexed Pell number, thus it is also a Markov number, appearing in the solutions (2, 169, 985), (2, 29, 169), (29, 169, 14701), etc. 169 is the sum of seven consecutive primes: 13 + 17 + 19 + 23 + 29 + 31 + 37. 169 is a difference in consecutive cubes, equaling

In astronomy

169 Zelia is a bright main belt asteroid
Gliese 169 is an orange, main sequence (K7 V) star in the constellation Taurus
QSO B0307+169 is a quasar in the constellation Aries
Sayh al Uhaymir 169 is a 206g lunar meteorite found in Sultanate of Oman

In geography

Pittville No. 169, Saskatchewan is a rural municipality in Saskatchewan, Canada
The state of Connecticut, which has no county governments, is divided into 169 towns

In the military

{{USNS|Private Jose F. Valdez|T-AG-169}} was a United States Navy technical research ship during the 1960s
{{USS|Chatham|AK-169}} was a United States Navy {{sclass-|Alamosa|cargo ship}} during World War II
{{USS|Gallatin|APA-169}} was a United States Navy {{sclass-|Haskell|attack transport}} during World War II
{{USS|Foote|DD-169}} was a United States Navy {{sclass-|Wickes|destroyer}} following World War I
{{USS|Atherton|DE-169}} was a United States Navy {{sclass-|Cannon|destroyer escort}} during World War II
{{USS|Dolphin|SS-169}} was a United States Navy submarine during World War II
169th Battalion, CEF unit in the Canadian Expeditionary Force during the World War I
169th Fires Brigade the US Army National Guard artillery brigade, a part of the Colorado Army National Guard
The United States Air Force's 169th Fighter Wing fighter unit at McEntire Joint National Guard Station, South Carolina
169 or 169th Squadrons
- 169th Airlift Squadron, a unit of the U.S. Air Force
- Marine Light Attack Helicopter Squadron 169, United States Marine Corps Light Attack Helicopter Squadron
- No. 169 Squadron RAF, a unit of the United Kingdom Royal Air Force

In transportation

[https://web.archive.org/web/20021002070149/http://transit.metrokc.gov/tops/bus/schedules/s169_0_.html Metro Transit Route 169] in Seattle
169th Street station on the IND Queens Boulevard Line of the New York City Subway served by the {{NYCS|E}} and {{NYCS|F}} trains
169th Street was a station on the demolished IRT Third Avenue Line of the New York City Subway

In TV and radio

The IEC 169-2 connector TV aerial plug

In other fields

169 is also:

The year AD 169 or 169 BC
The atomic number of an element temporarily called Unhexennium
169 is the number of nonequivalent starting hands in the card game Texas hold 'em
169 is known in the computing world as the first number of an automatic IPv4 address assigned by TCP/IP when no external networking device is contactable
Minuscule 169 is a Greek minuscule manuscript of the New Testament, on parchment

External links

Number Facts and Trivia: 169
The Positive Integer 169
Prime curiosities: 169
[https://web.archive.org/web/20160307161301/http://numdic.com/169 The Number 169]
VirtueScience: 169
Number Gossip 169

References

1. ^{{Cite web|url=https://oeis.org/A003215|title=Sloane's A003215 : Hex (or centered hexagonal) numbers|last=|first=|date=|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-05-28}}

1 : Integers

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