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+1
41
4
avatar+27 

What are the numbers strictly having "prime" factors between 30 & 140 only? It should be between 10000 & 20000

 May 2, 2022
 #1
avatar+117116 
+1

What are the numbers? Do you want us to list them? All 10 to 20 thousand of them?

 May 2, 2022
 #2
avatar+27 
+1

10001 to 19321, having prime factors between 30 & 140 only

10001 is 73 x 137 and 19321 is square of 139

GP72022a  May 2, 2022
 #3
avatar+117116 
+4

Firstly you need to work out how many prime factors there are between 30 and 140

 

You can do that with a seive of Eratosthense.

 

 May 2, 2022
 #4
avatar+27 
0

How about use 24(nCr)2 =276+ 24squares(31^2, 37^2, 41^2, 43^2, 47^2,.....and so on to 139^2

GP72022a  May 9, 2022

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