Double Twin Primes: Difference between revisions

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Find and show here all Double Twin Primes under 1000.
Find and show here all Double Twin Primes under 1000.
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=={{header|Raku}}==
<syntaxhighlight lang="raku" line>sub dt { $^p, $p+2, $p+6, $p+8 }
.&dt.say for (^1000).grep: { all .&dt».is-prime };</syntaxhighlight>
{{out}}
<pre>(5 7 11 13)
(11 13 17 19)
(101 103 107 109)
(191 193 197 199)
(821 823 827 829)</pre>

=={{header|Ring}}==
=={{header|Ring}}==
<syntaxhighlight lang="ring">
<syntaxhighlight lang="ring">

Revision as of 16:10, 24 March 2023

Definition
Let (p1,p2) and (p3,p4) be twin primes where p3 - p2 = 4.
Such primes called Double Twin Primes

Example
[5,7,11,13]
Task
Find and show here all Double Twin Primes under 1000.

Raku

sub dt { $^p, $p+2, $p+6, $p+8 }
.&dt.say for (^1000).grep: { all .&dt».is-prime };
Output:
(5 7 11 13)
(11 13 17 19)
(101 103 107 109)
(191 193 197 199)
(821 823 827 829)

Ring

see "works..." + nl
primes = []
limit = 1000
for n =1 to limit
    if isPrime(n)
       add(primes,n)
    ok
next
lenPrimes = len(primes)-3
for m = 1 to lenPrimes
    if isPrime(primes[m]) and isPrime(primes[m+1]) and 
       isPrime(primes[m+2]) and isPrime(primes[m+3])
       if (primes[m+1] - primes[m] = 2) and (primes[m+2] - primes[m+1] = 4) and 
          (primes[m+3] - primes[m+2] = 2)
          see " " + primes[m]+ " " + primes[m+1] + " " +
          primes[m+2] + " " + primes[m+3] + nl
       ok
    ok
next
see "done..." + nl

func isPrime num
     if (num <= 1) return 0 ok
     if (num % 2 = 0 and num != 2) return 0 ok
     for i = 3 to floor(num / 2) -1 step 2
         if (num % i = 0) return 0 ok
     next
     return 1
Output:
works...
 5 7 11 13
 11 13 17 19
 101 103 107 109
 191 193 197 199
 821 823 827 829
done...