Table image link http://postimg.org/image/v57ixyddr/
The above table tells about periodicity of occurrence of products of two numbers that can be represented by general formula $6k +1$ or $6k-1$
I don't understand the meaning of last column. What do numbers $30, 42, 66, 78, 102$ and $114$ represent in last column ? How the values of last column is being calculated ?