<PRIVATE
: next-collatz ( n -- n )
- dup even? [ 2 / ] [ 3 * 1+ ] if ;
+ dup even? [ 2 / ] [ 3 * 1 + ] if ;
: longest ( seq seq -- seq )
2dup [ length ] bi@ > [ drop ] [ nip ] if ;
<PRIVATE
: worth-calculating? ( n -- ? )
- 1- 3 { [ divisor? ] [ / even? ] } 2&& ;
+ 1 - 3 { [ divisor? ] [ / even? ] } 2&& ;
PRIVATE>