sequences: fix example in join-as.
sequences: fix example in join-as.

tgunr/factor,mrjbq7/factor,factor/factor,factor/factor,tgunr/factor,bpollack/factor,mrjbq7/factor,factor/factor,mrjbq7/factor,bpollack/factor,tgunr/factor,bpollack/factor,mrjbq7/factor,tgunr/factor,tgunr/factor,factor/factor,bpollack/factor,tgunr/factor,mrjbq7/factor,factor/factor,bpollack/factor,bpollack/factor,bpollack/factor,factor/factor,mrjbq7/factor