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### Re: Project Euler (a series of challenging mathematical/computer programming problems)

 on Feb 11, 2006 at 21:56 UTC ( #529603=note: print w/replies, xml ) Need Help??

here's another one i thought was correct: 77.
```my \$target = 5_001;  # also tried 5_000
my \$max = 1_000_000;

my @primes;
my \$sieve = '';

# generate list of primes
for (my \$try=2; \$try <= \$max; \$try++)
{
next if vec(\$sieve, \$try, 1);
push @primes, \$try;
for (my \$mults=\$try*\$try; \$mults <= \$max; \$mults+=\$try)
{
vec(\$sieve, \$mults, 1) = 1;
}
}

# number of composites <= n
# http://research.att.com/~njas/sequences/A065855
#
# equivalent to number of primes between prime(n) and n, so that's wha
+t
# i'm doing here
for (my \$i=0; \$i<@primes; \$i++)
{
my \$j = 0;
\$j++ while \$primes[\$j] <= \$i+1;

my \$count = 0;
\$j++ && \$count++ while \$primes[\$j] < \$primes[\$i];

next if \$count < \$target;
printf "%d: %d\n", \$i+1, \$count;
last;
}
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