Strong and weak primes: Difference between revisions

=={{header|Factor}}==

<lang factor>USING: formatting grouping kernel math math.primes sequences

tools.memory.private ;

IN: rosetta-code.strong-primes

: fn ( p-1 p p+1 -- p sum ) rot + 2 / ;

: strong? ( p-1 p p+1 -- ? ) fn > ;

: weak? ( p-1 p p+1 -- ? ) fn < ;

: swprimes ( seq quot -- seq )

[ 3 <clumps> ] dip [ first3 ] prepose filter [ second ] map

; inline

: stats ( seq n -- firstn count1 count2 )

[ head ] [ drop [ 1e6 < ] filter length ] [ drop length ]

2tri [ commas ] bi@ ;

10,000,019 primes-upto [ strong? ] over [ weak? ]

[ swprimes ] 2bi@ [ 36 ] [ 37 ] bi* [ stats ] 2bi@

"First 36 strong primes:\n%[%d, %]

%s strong primes below 1,000,000

%s strong primes below 10,000,000\n

First 37 weak primes:\n%[%d, %]

%s weak primes below 1,000,000

%s weak primes below 10,000,000\n" printf</lang>

{{out}}

<pre>

First 36 strong primes:

{ 11, 17, 29, 37, 41, 59, 67, 71, 79, 97, 101, 107, 127, 137, 149, 163, 179, 191, 197, 223, 227, 239, 251, 269, 277, 281, 307, 311, 331, 347, 367, 379, 397, 419, 431, 439 }

37,723 strong primes below 1,000,000

320,991 strong primes below 10,000,000

First 37 weak primes:

{ 3, 7, 13, 19, 23, 31, 43, 47, 61, 73, 83, 89, 103, 109, 113, 131, 139, 151, 167, 181, 193, 199, 229, 233, 241, 271, 283, 293, 313, 317, 337, 349, 353, 359, 383, 389, 401 }

37,780 weak primes below 1,000,000

321,750 weak primes below 10,000,000

</pre>