RosettaCodeData/Task/Twin-primes/Factor/twin-primes.factor
2023-07-01 13:44:08 -04:00

9 lines
338 B
Factor

USING: io kernel math math.parser math.primes.erato math.ranges
sequences tools.memory.private ;
: twin-pair-count ( n -- count )
[ 5 swap 2 <range> ] [ sieve ] bi
[ over 2 - over [ marked-prime? ] 2bi@ and ] curry count ;
"Search size: " write flush readln string>number
twin-pair-count commas write " twin prime pairs." print