is this possible

if A is a prime number then A + 100 is also prime is A is not a part of the following series

2,5,8,11,14,17,20,23,26............

prove it also

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- Oct 8th 2009, 06:16 PMjashansinghalprime number
is this possible

if A is a prime number then A + 100 is also prime is A is not a part of the following series

2,5,8,11,14,17,20,23,26............

prove it also - Oct 8th 2009, 06:59 PMchisigma
Counterexample: $\displaystyle 19$ is prime and is not included in the sequence $\displaystyle a_{n} = 2+3n$, but $\displaystyle 119=7\cdot 17$ is not a prime...

Kind regards

$\displaystyle \chi$ $\displaystyle \sigma$ - Oct 9th 2009, 07:16 AMjashansinghal
leaving 19 ,

is there a possibility - Oct 9th 2009, 07:38 PMchisigma
Further counterexample: $\displaystyle 103 \ne 3n-1$ is prime, $\displaystyle 203 = 7\cdot 29$ is not a prime...

Kind regards

$\displaystyle \chi$ $\displaystyle \sigma$ - Oct 10th 2009, 03:34 PMaidan
There are over 300 counter examples for numbers less than 10 thousand.