Generate six sets of random numbers using the formula xn$+1=($axn $+$ c$)$ mod m $.$

where x$0=3,$ a $=21,$ c $=7,$ and m $=50,100,500,1000,5000,10000.$ Name the random sets as list $1,$ list $2,...,$ list $6.$ Save these six sets to a $.$mat file with the filename random list.mat. $($Hint: you can use the function save to save several sets into a $.$mat file$)$