Any integer that can not be divided exactly by 2.
" (2n-1) "
n=1 => 2*1-1=1
n=2 => 2*2-1=3
n=3 => 2*3-1=5
(1,3,5,7,9......................2n-1)
Even numbers.
Even numbers can be divided evenly into groups of 2
"2n"
n=1 => 2*1 =2
n=2 => 2*2 =4
n=3 => 2*3 =6
(2,4,6,8,10........................2n)
