Math Is Fun Forum

Nike

Member

Registered: 2006-08-15

Posts: 1

About Special Numbers!

I want to know , what's the math name about such a special numbers:
A natural number, N, that can be written as the sum and product of a given set of at least two natural numbers, {a1, a2, ... , ak} is called a product-sum number: N = a1 + a2 + ... + ak = a1 a2 ... ak.

For example, 6 = 1 + 2 + 3 = 1 2 3.

is there any website solve this number like pi=3.1415.......and what 's its name? (like: An "NSW number"  (named after Newman, Shanks, and Williams) is an integer m that solves the Diophantine equation 2n^2==m^2+1)

any assistance will be appreciated!

krassi_holmz

Real Member

Registered: 2005-12-02

Posts: 1,905

Re: About Special Numbers!

which number I can't understand.
It seems interesting. Could you give more explanations?

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IPBLE:  Increasing Performance By Lowering Expectations.

Zhylliolom

Real Member

Registered: 2005-09-05

Posts: 412

Re: About Special Numbers!

I believe you are talking about perfect numbers in the first part of your post(the part where you talked about 6).

I'm not sure exactly what to make of the rest of the post.

Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: About Special Numbers!

I believe a special number is one that can be written as a sum of 2 or more consecutive numbers.

At least that's what my professor called it, but I can't seem to find it anywhere on the internet.

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

krassi_holmz

Real Member

Registered: 2005-12-02

Posts: 1,905

Re: About Special Numbers!

I tryed wiki and google but I couldn't find anything.

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IPBLE:  Increasing Performance By Lowering Expectations.

ben

Member

Registered: 2006-07-12

Posts: 106

Re: About Special Numbers!

Try here for some fun along these lines

http://www.trottermath.net/numtrivia/specnum.html

krassi_holmz

Real Member

Registered: 2005-12-02

Posts: 1,905

Re: About Special Numbers!

interesting link

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IPBLE:  Increasing Performance By Lowering Expectations.