Problem 1826. Find vampire numbers

Created by Andrew Newell

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A <a href = "http://en.wikipedia.org/wiki/Vampire_number">vampire number</a> is a
number v that is the product of two numbers x and y such that the
following conditions are satisfied:<ol><li>at most one of x and y are divisible by 10;</li><li>x and y have the same number of digits; and</li><li>The digits in v consist of the digits of x and y (including any
repetitions).</li></ol>If these conditions are met, x and y are known as "fangs" of v. For
example, 1260 is a vampire number because 1260 = 21*60, so 21 and 60 are
the fangs.Write a function that returns all the vampire numbers in a given array.
The output is a vector.Example:
 disp(find_vampire(1000:2000)
 1260 1395 1435 1530 1827See also:
 <a href = "http://www.mathworks.com/matlabcentral/cody/problems/1825-find-all-vampire-fangs">Problem 1825. Find all vampire fangs</a> and <a href = "http://www.mathworks.com/matlabcentral/cody/problems/1804-fangs-of-a-vampire-number">Problem 1804. Fangs of a vampire number</a>.

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Solution Stats

515 Solutions
148 Solvers

Last Solution submitted on Feb 24, 2021

Last 200 Solutions

Problem Comments

2 Comments

2 Comments

Rafael S.T. Vieira on 16 Jul 2020

Are you sure about the first rule? It doesn't seem necessary according to https://oeis.org/A014575.

Adib on 27 Jul 2020

The problem is really fun.

Solution Comments

Solution 1937166

1 Comment

1 Comment

Serhii Tetora on 24 Sep 2020

cheating

Solution 1183879

2 Comments

2 Comments

Andrew Newell on 9 May 2017

Since I created the problem series and want the Functions I badge, I thought I'd provide the solution that incorporates vampire_factor and are_fangs. Not a great score, but readable!

Andrew Newell on 9 May 2017

Sorry, I mean the Magic Numbers badge.

Solution 678164

1 Comment

1 Comment

danteliujie on 7 Apr 2019

Like it

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Problem Tags

factors number theory

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