Double Twin Primes: Difference between revisions

=={{header|Nim}}==

<syntaxhighlight lang="Nim">import std/strformat

func isPrime(n: Positive): bool =

if n < 2: return false

if (n and 1) == 0: return n == 2

if n mod 3 == 0: return n == 3

var k = 5

var delta = 2

while k * k <= n:

if n mod k == 0: return false

inc k, delta

delta = 6 - delta

result = true

echo "Double twin primes under 1000:"

for n in countup(3, 991, 2):

if isPrime(n) and isPrime(n + 2) and isPrime(n + 6) and isPrime(n + 8):

echo &"({n:>3}, {n+2:>3}, {n+6:>3}, {n+8:>3})"

</syntaxhighlight>

{{out}}

<pre>( 5, 7, 11, 13)

( 11, 13, 17, 19)

(101, 103, 107, 109)

(191, 193, 197, 199)

(821, 823, 827, 829)

</pre>