after 2 all primes are odd, but odd numbers have 2 or more of sum

consecutive numbers, for example,

9 = 4 + 5 and 9 = 2 + 3 + 4

15 = 7 + 8 and 15 = 4 + 5 + 6, 15 = 1 + 2 + 3 + 4 + 5

but, prime number only can be built by 2 consecutive number

is that right?

if it is right, maybe the first prime number (2), have important

meaning.

--- In

primenumbers@yahoogroups.com, "Paul Leyland" <pleyland@m...>

wrote:

> > except 2, every prime number is always sum of

> > consecutive integer or

> > every prime is always staircase numbers

> > 3, = 1 + 2

> > ...

> >

> > any idea ?

>

> After 2, all primes are odd and so of the form 2i+1. Your

observation is then

> trivial.

>

> (HIBT?)

>

>

> Paul