# What is next number in the series 1,2,3,5,7,11,_

Posted by Virendradugar on 12/20/2009 | Category: Aptitute Test Interview questions | Views: 26901
Select from following answers:
1. 13
2. 15
3. 12
4. 17
5. All Above

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#### Comments or Responses

Posted by: Nikhil33453 on: 6/28/2012 | Points: 10
Answer is 13 because all the given no in series are prime no in sequence and hence after 11 no the prime
no is 13
Posted by: Kossovsky on: 7/13/2012 | Points: 10
You should remove 1 from the series as it is not a prime number
A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself
Posted by: Shariq on: 12/1/2012 | Points: 10
A prime is the number which have two different divisors, one divisor is 1, and other one the number itself. so we can not put 1 in the series of prime numbers as 1 has only one divisor that is 1( itself).
Posted by: At1 on: 11/4/2015 | Points: 10
1 2 3 5 7 11 15 is well-known sequence «number of partitions of n (the partition numbers)»
https://oeis.org/A000041

As mentioned before, answer 13 is incorrect because of 1 is not prime.
You should fix correct answer for this question on 15.
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