slight cleanup in memoize
slight cleanup in memoize

bjourne/factor,AlexIljin/factor,dch/factor,sarvex/factor-lang,tgunr/factor,jwmerrill/factor,tgunr/factor,ehird/factor,nicolas-p/factor,factor/factor,tgunr/factor,mcandre/factor,ehird/factor,nicolas-p/factor,slavapestov/factor,tgunr/factor,erg/factor,slavapestov/factor,Keyholder/factor,Keyholder/factor,mrjbq7/factor,ceninan/factor,erg/factor,bjourne/factor,AlexIljin/factor,cataska/factor,seckar/factor,littledan/Factor,nicolas-p/factor,kingcons/factor,factor/factor,sarvex/factor-lang,mcandre/factor,cataska/factor,bpollack/factor,bpollack/factor,dch/factor,cataska/factor,nicolas-p/factor,littledan/Factor,kingcons/factor,seckar/factor,bjourne/factor,dch/factor,AlexIljin/factor,erg/factor,AlexIljin/factor,jwmerrill/factor,mcandre/factor,littledan/Factor,jwmerrill/factor,kingcons/factor,seckar/factor,bjourne/factor,factor/factor,slavapestov/factor,slavapestov/factor,sarvex/factor-lang,bpollack/factor,AlexIljin/factor,nicolas-p/factor,bpollack/factor,dch/factor,sarvex/factor-lang,sarvex/factor-lang,dch/factor,slavapestov/factor,slavapestov/factor,mrjbq7/factor,mcandre/factor,bpollack/factor,AlexIljin/factor,ceninan/factor,mrjbq7/factor,erg/factor,mcandre/factor,cataska/factor,factor/factor,ehird/factor,erg/factor,nicolas-p/factor,mrjbq7/factor,ceninan/factor,bpollack/factor,mcandre/factor,factor/factor,sarvex/factor-lang,tgunr/factor,kingcons/factor,slavapestov/factor,mcandre/factor,tgunr/factor,mrjbq7/factor,bpollack/factor,dch/factor,bjourne/factor,littledan/Factor,ceninan/factor,factor/factor,mrjbq7/factor,erg/factor,bjourne/factor,erg/factor,nicolas-p/factor,AlexIljin/factor,Keyholder/factor,bjourne/factor,sarvex/factor-lang