Discover the Pattern of PDS Numbers and Find the Nth PDS Number

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SUMMARY

The discussion focuses on identifying PDS (Product-Divisible Sum) numbers, defined as numbers where the product of their digits is divisible by the sum of their digits. The series of PDS numbers includes 1 through 10, multiples of 22, and numbers containing at least one zero. Notably, numbers like 36 and 63 are included despite not fitting the initial criteria. Participants express the need for a general term to efficiently find the nth PDS number, although one contributor suggests that no general formula exists, recommending an algorithmic approach instead.

PREREQUISITES
  • Understanding of basic number theory concepts, including divisibility.
  • Familiarity with digit manipulation in numbers.
  • Basic programming skills for algorithm development.
  • Knowledge of mathematical series and sequences.
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  • Research algorithms for generating sequences of numbers based on specific criteria.
  • Explore mathematical properties of divisibility and digit products.
  • Learn about efficient number generation techniques in programming languages like Python.
  • Investigate existing mathematical literature on PDS numbers and similar sequences.
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Mathematicians, computer scientists, and programmers interested in number theory, algorithm design, and those seeking to optimize calculations related to digit-based properties of numbers.

shekhar kumar
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PDS number:> a number whose product of digits is completely divisible by sum of its digits.
Now the series comes out to be: 1,2,3,4,5,6,7,8,9,10,20,22,30,36,40,44,50,60,63,66,70... so on.
(1. Numbers from 1 to 10 are already divisible by themselves.
2. Then all the multiples of 22 follow the pds series completely.
3. And finally all the numbers which contains atleast one zero are also pds number).
I have to find the general term of this pds series so that i can find the nth pds number in a single shot.
Plz help in doing that as soon as possible.
Thanks in advance...
 
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you have said three conditions...in that case how the numbers 36,63...will come in the list...they are neither containing zero...nor multiples of 22...


shekhar kumar said:
PDS number:> a number whose product of digits is completely divisible by sum of its digits.
Now the series comes out to be: 1,2,3,4,5,6,7,8,9,10,20,22,30,36,40,44,50,60,63,66,70... so on.
(1. Numbers from 1 to 10 are already divisible by themselves.
2. Then all the multiples of 22 follow the pds series completely.
3. And finally all the numbers which contains atleast one zero are also pds number).
I have to find the general term of this pds series so that i can find the nth pds number in a single shot.
Plz help in doing that as soon as possible.
Thanks in advance...
 
shekhar kumar said:
PDS number:> a number whose product of digits is completely divisible by sum of its digits.
Now the series comes out to be: 1,2,3,4,5,6,7,8,9,10,20,22,30,36,40,44,50,60,63,66,70... so on.
(1. Numbers from 1 to 10 are already divisible by themselves.
2. Then all the multiples of 22 follow the pds series completely.
3. And finally all the numbers which contains atleast one zero are also pds number).
I have to find the general term of this pds series so that i can find the nth pds number in a single shot.
Plz help in doing that as soon as possible.
Thanks in advance...

I don't think there is any general formula for finding the nth term. You could of course write an algorithm that generates the nth digit but the time would increase exponentially with the size of n.

BiP
 

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