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