Palindromic primes in base 16: Difference between revisions
added AWK
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<pre>
2 3 5 7 B D 11 101 151 161 191 1B1 1C1
</pre>
=={{header|AWK}}==
<lang AWK>
# syntax: GAWK -f PALINDROMIC_PRIMES_IN_BASE_16.AWK
BEGIN {
start = 1
stop = 499
for (i=start; i<=stop; i++) {
hex = sprintf("%X",i)
if (is_prime(i) && hex == reverse(hex)) {
printf("%4s%1s",hex,++count%10?"":"\n")
}
}
printf("\nPalindromic primes %d-%d: %d\n",start,stop,count)
exit(0)
}
function is_prime(x, i) {
if (x <= 1) {
return(0)
}
for (i=2; i<=int(sqrt(x)); i++) {
if (x % i == 0) {
return(0)
}
}
return(1)
}
function reverse(str, i,rts) {
for (i=length(str); i>=1; i--) {
rts = rts substr(str,i,1)
}
return(rts)
}
</lang>
{{out}}
<pre>
2 3 5 7 B D 11 101 151 161
191 1B1 1C1
Palindromic primes 1-499: 13
</pre>
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