311 (number)

311 is the number after 310 and before 312.

Template:Numbers 0-1000
311
Cardinal	Three hundred eleven
Ordinal	311th
Factorization	Prime
Roman numeral	CCCXI
Binary	100110111
Hexadecimal	137

In mathematics

311 is a twin prime with 313, an Eisenstein prime with no imaginary part and real part of the form $3n-1$, a Gaussian prime with no imaginary part and real part of the form $4n-1$, and a permutable prime with 113 and 131.

It can be expressed as a sum of consecutive primes in three different ways: as a sum of three consecutive primes (101 + 103 + 107), as a sum of five consecutive primes (53 + 59 + 61 + 67 + 71), and as a sum of seven consecutive primes (31 + 37 + 41 + 43 + 47 + 53 + 59).

311 is a strictly non-palindromic number, it is not palindromic in any base from base 2 to base 309.

Other uses

• 311 is the name of a band, see 311 (band).

• 311 is also used as a non-emergency "hot line" telephone number for municipal government in some US cities, including Baltimore, Maryland, New York City, and San Jose, California, as an alternative to 911 for emergency use. Some cities also use the 3-1-1 number to allow citizens to obtain general information about the city. For example, a citizen who needs information about garbage collection might dial 3-1-1 for information. For detailed information, see 3-1-1.

• For the year 311 AD, see 311.

• 311 is considered slang for KKK, because K is the 11th letter of the English alphabet, so 3 11 is KKK. It is used by a gang in Las Vegas, known as the 311 Boyz. (A different breed: 311 Boyz are unlike other gangs)

• 311 is the number of times Timothy Leary claimed to have taken LSD in his interview with Playboy Magazine. The article is titled She Comes in Colors and it appears in the September 1996 issue. A reprint of the article appears in his book, The Politics of Ecstasy.