Safe and Sophie Germain primes: Difference between revisions
added AWK
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Catskill549 (talk | contribs) (added AWK) |
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953 1013 1019 1031 1049 1103 1223 1229 1289 1409 1439 1451
1481 1499
</pre>
=={{header|AWK}}==
<lang AWK>
# syntax: GAWK -f SAFE_AND_SOPHIE_GERMAIN_PRIMES.AWK
BEGIN {
limit = 50
printf("The first %d Sophie Germain primes:\n",limit)
while (count < limit) {
if (is_prime(++i)) {
if (is_prime(i+i+1)) {
printf("%5d%1s",i,++count%10?"":"\n")
}
}
}
exit(0)
}
function is_prime(n, d) {
d = 5
if (n < 2) { return(0) }
if (n % 2 == 0) { return(n == 2) }
if (n % 3 == 0) { return(n == 3) }
while (d*d <= n) {
if (n % d == 0) { return(0) }
d += 2
if (n % d == 0) { return(0) }
d += 4
}
return(1)
}
</lang>
{{out}}
<pre>
The first 50 Sophie Germain primes:
2 3 5 11 23 29 41 53 83 89
113 131 173 179 191 233 239 251 281 293
359 419 431 443 491 509 593 641 653 659
683 719 743 761 809 911 953 1013 1019 1031
1049 1103 1223 1229 1289 1409 1439 1451 1481 1499
</pre>
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