Quadrat special primes: Difference between revisions
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7247 7283 7607 7643 8219 8363 10667 11243 11279 11423
12323 12647 12791 13367 13691 14591 14627 14771 15671
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=={{header|Ksh}}==
<lang ksh>
#!/bin/ksh
# Quadrat Special Primes
# # Variables:
#
alias SHORTINT='typeset -si'
SHORTINT MAXN=16000
# # Functions:
#
# # Function _isquadrat(n, m) return 1 when (m-n) is a perfect square
#
function _isquadrat {
typeset _n ; SHORTINT _n=$1
typeset _m ; SHORTINT _m=$2
[[ $(( sqrt(_m - _n) )) == +(\d).+(\d) ]] && return 0
return 1
}
# # Function _isprime(n) return 1 for prime, 0 for not prime
#
function _isprime {
typeset _n ; integer _n=$1
typeset _i ; integer _i
(( _n < 2 )) && return 0
for (( _i=2 ; _i*_i<=_n ; _i++ )); do
(( ! ( _n % _i ) )) && return 0
done
return 1
}
######
# main #
######
SHORTINT i prev_pr=2
for ((i=2; i<MAXN; i++)); do
_isprime ${i}
if (( $? )); then
_isquadrat ${prev_pr} ${i}
if (( $? )); then
printf "%d " ${i}
prev_pr=${i}
fi
fi
done
printf "\n"
</lang>
{{out}}<pre>
2 3 7 11 47 83 227 263 587 911 947 983 1019 1163 1307 1451 1487 1523 1559 2459 3359 4259 4583 5483 5519 5843 5879 6203 6779 7103 7247 7283 7607 7643 8219 8363 10667 11243 11279 11423 12323 12647 12791 13367 13691 14591 14627 14771 15671
</pre>
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