Graham’s Number

Graham’s number is a number invented by Ronald Graham. In order to explain what it is, the notation must be understood. It’s called up-arrow notation, denoted by the ↑ symbol. One up-arrow just denotes that the second number is an exponent. For example, 3↑3 is 3^3, or 27. Using two arrow creates the fourth thing in the sequence of addition, multiplication, and exponentiation. Some call this math operation tetration. 3↑↑3 is 3^(3^3), 3^27, or 7,625,597,484,987. Using a third arrow, you can probably predict what happens. 3↑↑↑3 is 3↑↑(3↑↑3), or 3↑↑7,625,597,484,987. This means that you have (3^(3^(3^(...(3^3)...)))), and there are 7,625,597,484,987 3’s. For perspective, 3↑↑4, or 3^7,625,597,484,987, contains 3,638,334,640,024 digits. I’m not kidding, that is the actual number of digits, compute it using the Big Online Calculator. And yet, despite how far blown out of proportion this thing has been, it’s still not large enough. We need a fourth arrow. Don’t even get me started on the size of 3↑↑↑↑3, or 3↑↑↑(3↑↑↑3). And that number is called G(1). G(2) is 3↑↑↑...↑↑↑3. There are G(1) arrows. G(3) is 3↑↑↑...↑↑↑3, with G(2) 3’s. You get it now? Graham’s number is defined as G(64). And despite its immense size, it actually has a purpose. Suppose you had higher-dimensional hypercubes, and you had two colors for edges, and you wanted to know how many dimensions it took before a square where all lines were the same color was forced. The upper bound on that answer is Graham’s number.

Graham’s number is a number which was once considered the largest of all time.

by YeetusDeletus69420 January 5, 2020

Godwin's number

n. The average number of replies in a thread before a Nazi reference is made. Generally, Godwin's number is regarded to be twenty, based on the equation: G=(d(Q1)+d(Q2)+...+d(Q)n)/100*n^(-n)
where Qn is the intelligence of user n, n is the total number of forum users, and d is a damping function that prevents the intelligence (or lack there of) of one user to influence the others too much.

As he typed his polemic on the forum, John brought the discussion one step closer to Godwin's number.

To prevent discussions from getting out of hand, OmniForums will now calculate Godwin's number based on the first two threads.

by A_1_B_2_C_3_________________ September 30, 2006

number

Short form for "phone number."

Joe: So what happened with you and that girl at the bar?
Sammy: I got her number!
Joe: Sweet, you'll be banging her in no time!

by RexGibson March 11, 2004

take a number

Figurative: "If you want to discuss this topic with me, you will need to wait your turn, as there are any number of others who wish to do so who got here before you did."

Comes from a line control mechanism that is found today with decreasing frequency, where one is requested to take a numbered ticket from a strategically placed dispenser and accordingly wait for that number to be called.

Your computer just blew up? Take a number, I've been getting calls on that all day.

by ke6isf October 15, 2004

number plate

Identifying plates fitted to vehicles in the UK (and elsewhere), carrying the vehicle's registration number.
Similar to License plate, Registration plate etc.

In the UK the reg. no. belongs to the vehicle, not the driver, and contains information about the age of the vehicle and the region in which it was first sold. The system is administered by the DVLA.

The reg. number is alphanumeric, and takes the form AB12 CDE on vehicles registered after 2001, or A123 BCD on vehicles registered before 2001.

Some scouse git has stolen my number plates. Now I will be done by the police.

by oracle February 27, 2006

Erdős-number

The Erdős number (Hungarian pronunciation: ˈɛrdøːʃ) describes the "collaborative distance" between a person and mathematician Paul Erdős, as measured by authorship of mathematical papers.

Mathematician Daniel Kleitman have collaborated with Paul Erdős so his Erdős-number is 1.

by morino_kenta February 5, 2010

jimaginary number

A portmanteau of "j" and "imaginary" for the imaginary component of a complex number. This means the same thing as Imaginary Number, and typically this number would have an italicized i after it. In electrical engineering, the letter "i" has other and more apparent meanings, so to avoid confusion we pick the next letter, j.

Compare imaginary with jimaginary number
Sheldon would use 1 + 2i.
Howard would use 1 + 2j.

by brokenbrain October 25, 2011