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3-3-2008 12:01 PM414 views
skwirlinator says:
The original clip was too big so it went private. Since this is interesting mathematical information I reclipped it to share it with you.
8 Comments   | Add a Comment
3-3-2008 12:03 PM
skwirlinator
The original clip looks at all the numbers thru 9999
3-3-2008 1:50 PM
skwirlinator
The identity element of an additive group G, usually denoted 0. In the additive group of vectors, the additive identity is the zero vector 0, in the additive group of polynomials it is the zero polynomial P(x)=0, in the additive group of m×n matrices it is the m×n zero matrix.

SEE ALSO: Additive Group, Additive Inverse, Multiplicative Identity, Zero, Zero Matrix, Zero Polynomial, Zero Vector
3-3-2008 1:51 PM
skwirlinator
Multiply all the digits of a number n by each other, repeating with the product until a single digit is obtained. The number of steps required is known as the multiplicative persistence, and the final digit obtained is called the multiplicative digital root of n.
3-3-2008 1:52 PM
skwirlinator
Perfect numbers were deemed to have important numerological properties by the ancients, and were extensively studied by the Greeks, including Euclid.

Perfect numbers are also intimately connected with a class of numbers known as Mersenne primes, which are prime numbers of the form M_p=2^p-1.
3-3-2008 1:53 PM
skwirlinator
The Lucas numbers are the sequence of integers {L_n}_(n=1)^infty defined by the linear recurrence equation
L_n=L_(n-1)+L_(n-2)
3-3-2008 1:54 PM
skwirlinator
The Motzkin numbers enumerate various combinatorial objects. Donaghey and Shapiro (1977) give 14 different manifestations of these numbers. In particular, they give the number of paths from (0, 0) to (n, 0) which never dip below y=0 and are made up only of the steps (1, 0), (1, 1), and (1, -1), i.e., ->, ->, and ->.
3-3-2008 1:55 PM
skwirlinator
A generalization of the polyominoes using a collection of equal-sized equilateral triangles (instead of squares) arranged with coincident sides. Polyiamonds are sometimes simply known as iamonds.

The top row of hexiamonds in the above figure are known as the bar, crook, crown, sphinx, snake, and yacht. The bottom row of 6-polyiamonds are known as the chevron, signpost, lobster, hook, hexagon, and butterfly.

The number of two-sided (i.e., can be picked up and flipped, so mirror image pieces are considered identical) polyiamonds made up of n triangles are 1, 1, 1, 3, 4, 12, 24, 66, 160, 448, ... (Sloane's A000577). The number of one-sided polyiamonds composed of n triangles are 1, 1, ...
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3-4-2008 9:17 AM
Satchamo
Thanks skwirlinator for the clip! Brought back memories of my Number Theory class in college. I enjoyed learning about the different types of numbers--perfect, amicable numbers, friendly numbers, solitary numbers. etc.
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