Question

Complete the series - 7 , 31 , 211, , ? What will be the next term? Options are 2311 , 2211 , 2561 , 2781. Please help me with this.

Answer 1

Actually it is series of Euclid numbers : 7, 31, 211, 2311, 30031, 510511, 9699691

So accordingly:

7=2*3+1

31=2*3*5+1

show the next number is 23 11.
Hope it helped!!
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Answer 2

Answer:

Option 1 - 2311

Step-by-step explanation:

Given : Series 7 , 31 , 211,  ?

To find : What will be the next term?

Solution :

We have series 7 , 31 , 211,  ?

To determine the missing number we have to find the pattern.

So,

$7=2\times 3+1$

$31=2\times 3\times 5+1$

$211=2\times 3\times 5\times 7+1$

$2311=2\times 3\times 5\times 7\times 11+1$

i.e. multiple of prime numbers +1.

The missing term is 2311.

Therefore, option 1 is correct.