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.\" This code is derived from software contributed to Berkeley by
.\" Landon Curt Noll.
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.\"	@(#)factor.6	8.1 (Berkeley) 5/31/93
.\"
.\"
.\" By Landon Curt Noll, http://www.isthe.com/chongo/index.html /\oo/\
.\"
.Dd February 3, 2008
.Dt PRIMES 6
.Os
.Sh NAME
.Nm primes
.Nd generate primes
.Sh SYNOPSIS
.Nm primes
.Op Fl d
.Op Fl h
.Op Ar start Op Ar stop
.Sh DESCRIPTION
The
.Nm
utility prints primes in ascending order, one per line, starting
at or above
.Ar start
and continuing until, but not including
.Ar stop .
The
.Ar start
value must be at least 0 and not greater than
.Ar stop .
The
.Ar stop
value must not be greater than 3825123056546413050.
The default value of
.Ar stop
is 3825123056546413050.
.Pp
When the
.Nm
utility is invoked with no arguments,
.Ar start
is read from standard input and
.Ar stop
is taken to be 3825123056546413050.
The
.Ar start
value may be preceded by a single
.Sq \&+ .
The
.Ar start
value is terminated by a non-digit character (such as a newline).
The input line must not be longer than 255 characters.
.Pp
When given the
.Fl d
argument,
.Nm
prints the difference between the current and the previous prime.
.Pp
When given the
.Fl h
argument,
.Nm
prints the prime numbers in hexadecimal.
.Sh DIAGNOSTICS
Out of range or invalid input results in
an appropriate error message to standard error.
.Sh AUTHORS
Originally by
.An Landon Curt Noll ,
extended to some 64-bit primes by
.An Colin Percival .
.Sh CAVEATS
This
.Nm
program won't get you a world record.
.Pp
The program is not able to list primes between
3825123056546413050 and 18446744073709551615 (2^64
- 1) as it relies on strong pseudoprime tests after
sieving, and it is yet unknown how many of those
tests are needed to prove primality for integers
larger than 3825123056546413050.