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Problem 1394. Prime Ladders

Created by Ned Gulley

A word ladder transforms one word to another by means of single-letter mutations. So COLD can become WARM like so (there are often multiple solutions):

 COLD
 CORD
 CARD
 WARD
 WARM

A number ladder does much the same thing, changing one digit at a time. A prime ladder is a number ladder with the additional constraint that each element is a prime number. Here is a prime ladder that connects 757 and 139

 757 
 157
 137
 139

Given two numbers p1 and p2, construct a prime ladder column vector in which p1 is the first element, p2 is the last element, and each successive row differs by exactly one digit from the preceding element.

To restate the above example, consider

 p1 = 757
 p2 = 139

for which an acceptable answer is

 ladder = [757; 157; 137; 139]

You can assume that p1 and p2 contain the same number of digits. I am not looking for a unique answer. I will only check that the conditions of a prime ladder are met.

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9 correct solutions 9 incorrect solutions
Last solution submitted on Aug 28, 2014

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