a<-"a"
letra.a<-rep(a,times=6)
numeros<-rep(1:3,c(3,3,3))
decrescente<-rep(1:3,c(3,2,1))
x<-seq(1,4)
y<-seq(4,1)
sequencia<-c(x,5,y)
impares<-seq(1,99,by=2)