sequences: use check-length to force integer partial dispatch in iteration.
sequences: use check-length to force integer partial dispatch in iteration.

factor/factor,bjourne/factor,AlexIljin/factor,slavapestov/factor,AlexIljin/factor,tgunr/factor,tgunr/factor,bpollack/factor,nicolas-p/factor,bpollack/factor,bjourne/factor,nicolas-p/factor,bjourne/factor,nicolas-p/factor,factor/factor,mrjbq7/factor,AlexIljin/factor,slavapestov/factor,AlexIljin/factor,bjourne/factor,slavapestov/factor,slavapestov/factor,factor/factor,tgunr/factor,nicolas-p/factor,mrjbq7/factor,factor/factor,bjourne/factor,AlexIljin/factor,slavapestov/factor,mrjbq7/factor,slavapestov/factor,bpollack/factor,bjourne/factor,bpollack/factor,bjourne/factor,AlexIljin/factor,factor/factor,mrjbq7/factor,mrjbq7/factor,bpollack/factor,tgunr/factor,factor/factor,mrjbq7/factor,nicolas-p/factor,tgunr/factor,slavapestov/factor,bpollack/factor,tgunr/factor,AlexIljin/factor,nicolas-p/factor,bpollack/factor,nicolas-p/factor