Expanding a column containing list in a dataframe to a row

Hi,

My source data is this

> x<-c(10,15)
> y<-c(20,33)
> z<-c(4,8)
> a<-data.frame(x,y,z)
> names(a)<-c("F","T","L")

I performed following

> T1<- function(a,b,c){
+     x1<-seq(from=a,to=b,length=c)
+ }
> a$Sam<-mapply(T1,a$F,a$T,a$L)
> a

It results in a dataframe where I guess the column "Sam" contains list.

 F  T L                                                                            Sam
1 10 20 4                                         10.00000, 13.33333, 16.66667, 20.00000
2 15 33 8 15.00000, 17.57143, 20.14286, 22.71429, 25.28571, 27.85714, 30.42857, 33.00000

Is it possible to achieve the following dataframe as the final output
https://drive.google.com/open?id=186gJxpt6MYph1PvWCAQYM9khZGhlfA04

Thank you in advance.