Integer sequences

Refactorable number

A refactorable number or tau number is an integer n that is divisible by the count of its divisors, or to put it algebraically, n is such that . The first few refactorable numbers are listed in (sequence in the OEIS) as 1, 2, 8, 9, 12, 18, 24, 36, 40, 56, 60, 72, 80, 84, 88, 96, 104, 108, 128, 132, 136, 152, 156, 180, 184, 204, 225, 228, 232, 240, 248, 252, 276, 288, 296, ... For example, 18 has 6 divisors (1 and 18, 2 and 9, 3 and 6) and is divisible by 6. There are infinitely many refactorable numbers. (Wikipedia).

Refactorable number
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Divisibility Rules

This video covers the divisibility rules for 2,3,4,5,6,8,9,and 10. http://mathispower4u.yolasite.com/

From playlist Factors, Prime Factors, and Least Common Factors

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Ex 1: Apply Divisibility Rules to a 4 Digit Number

This video explains how to apply the divisibility rules for 2, 3, 4, 5, 6, 8, 9, and 10. http://mathispower4u.com

From playlist Factors, Prime Factors, and Least Common Factors

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From playlist Math Foundations

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From playlist How to multiply and divide decimals

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Ex 2: Apply Divisibility Rules to a 4 Digit Number

This video explains how to apply the divisibility rules for 2, 3, 4, 5, 6, 8, 9, and 10. http://mathispower4u.com

From playlist Factors, Prime Factors, and Least Common Factors

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👉 Learn how to convert numbers from scientific notations. Scientific notation is a convenient way of writing very large or very small numbers. A number written in scientific notation is of the form a * 10^n where a is the first non-zero number between 1 and 10, (1 included) and n is the nu

From playlist How to Convert Scientific Notation to a Number

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Ex: Linear Equation Application with One Variable - Number Problem

This video provides and example of how to solve a number problem using a linear equation with one variable. One number is a multiple of the other. The difference is a constant. Find the two numbers. Library: http://mathispower4u.com Search: http://mathispower4u.wordpress.com

From playlist Whole Number Applications

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Learn how to multiply a three digit decimal to a two digit decimal

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From playlist How to multiply and divide decimals

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How to use decimal points

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From playlist Decimals | Learn About

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MountainWest RubyConf 2015 - Data-Driven Refactoring

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From playlist MWRC 2015

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From playlist RubyConf 2016

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From playlist Excalibur

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Virtual EmberConf 2020: Programmer's Bookshelf: Cliff Notes Edition by Lisa Backer

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From playlist EmberConf 2020

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How To (Semi-)Automate JavaScript Refactoring - Giles Bowkett

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From playlist Fluent Conference 2013

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From playlist Excalibur

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From playlist Code Refactoring

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From playlist Wicked Good Ember 2015

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If you don't already know Numberphile, go and subscribe right now to their channel.

From playlist Other...

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Help us caption & translate this video! http://amara.org/v/FGiU/

From playlist Cascadia Ruby 2012

Related pages

Perfect number | Graph theory | Natural density | Greatest common divisor | Divisor | Number theory | Divisor function