Math puzzle #2

[Evada]

Because seniors complained that my first puzzle was too easy, here's the 2nd one (a bit tougher):

 

[Sunny]

Too hard for me. Hint, maybe?

 

[Sassycakes]

Just a guess 15?

 

[tinytn]

^^^that's what i was going to say Sassycakes.

i will go with # 8 ?

 

[Evada]

OK, hint for Sunny: think at the first 6 prime numbers.
Sassycakes and tinytn: it's not 15 or 8
And an easier one below

 

[tinytn]

i have no idea, but guessing .... #111

 

[Evada]

i have no idea, but guessing .... #111

The first 5 prime numbers are 2, 3, 5, 7 and 11. Let p be the prime number, so then calculate x = p^2 + 1:
p = 2 => x = 2^2 + 1 = 4 + 1 = 5
p = 3 => x = 3^2 + 1 = 9 + 1 = 10
p = 5 => x = 5^2 + 1 = 25 + 1 = 26 = ? (what the question was)
p = 7 => x = 7^2 + 1 = 49 + 1 = 50
p = 11 => x = 11^2 + 1 = 121 + 1 = 122

 

[Sunny]

By George, she's got it! Congrats, Evada!