Cousin primes: Difference between revisions

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 971
 There are 41 cousin prime pairs below 1000</pre>
+=={{header|BCPL}}==
+<lang bcpl>get "libhdr"
+manifest $( LIMIT = 1000 $)
+let sieve(prime,max) be
+$(  let i = 2
+!prime := false
+!prime := false
+    for i = 2 to max do i!prime := true
+    while i*i <= max do
+    $(  if i!prime do
+        $(  let j = i*i
+            while j <= max do
+            $(  j!prime := false
+                j := j + i
+            $)
+        $)
+        i := i + 1
+    $)
+$)
+let start() be
+$(  let prime = vec LIMIT
+    let count = 0
+    sieve(prime, LIMIT)
+    for i = 2 to LIMIT-4 do
+        if i!prime & (i+4)!prime do
+        $(  count := count + 1
+            writef("%N, %N*N", i, i+4)
+        $)
+    writef("*N%N pairs found.*N", count)
+$)</lang>
+{{out}}
+<pre style="height:14em;">3, 7
+, 11
+, 17
+, 23
+, 41
+, 47
+, 71
+, 83
+, 101
+, 107
+, 113
+, 131
+, 167
+, 197
+, 227
+, 233
+, 281
+, 311
+, 317
+, 353
+, 383
+, 401
+, 443
+, 461
+, 467
+, 491
+, 503
+, 617
+, 647
+, 677
+, 743
+, 761
+, 773
+, 827
+, 857
+, 863
+, 881
+, 887
+, 911
+, 941
+, 971
+pairs found.</pre>
 =={{header|C}}==