Originally posted by geepamoogle My guess would be a prime number around 250-260, but I have yet to find any rule which explains how you arrive at each number.

Originally posted by geepamoogle My guess would be a prime number around 250-260, but I have yet to find any rule which explains how you arrive at each number.

Can we have a hint?

Coincidence or help? (Obviously 3 does not fit pattern)

Originally posted by Thomaster Is 1 a prime number?

Not technically, no. But 1 is part of the series and hint. It's as if you started counting 1 through 10, but skipped 2, and 4-12. (although that's not the answer)

A prime number has exactly two integer divisors, 1 and itself.
A composite number has 3 or more divisors.

1 only has a singular divisor, itself. It is the only counting number with this property.

For most mathematical purposes, 1 isn't considered 'prime', but rather a multiplicative identity. For instance, 1 isn't listed for prime factorization of a number.

That being said, it would seem for the purposes of this pattern, 1 is considered prime, and as such I will accept it.