Find prime n such that reversed n is also prime: Difference between revisions
Find prime n such that reversed n is also prime (view source)
Revision as of 20:28, 22 March 2021
, 3 years agoAdded Delphi example
(Added Go) |
MaiconSoft (talk | contribs) (Added Delphi example) |
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Found 34 reversable primes below 500
</pre>
=={{header|Delphi}}==
{{libheader| System.SysUtils}}
{{libheader| PrimTrial}}
{{Trans|Ring}}
<lang Delphi>
program Find_prime_n_for_that_reversed_n_is_also_prime;
{$APPTYPE CONSOLE}
uses
System.SysUtils,
PrimTrial;
function Reverse(s: string): string;
var
i: Integer;
begin
Result := '';
if Length(s) < 2 then
exit(s);
for i := Length(s) downto 1 do
Result := Result + s[i];
end;
begin
writeln('working...'#10);
var row := 0;
var count := 0;
var limit := 500;
for var n := 1 to limit - 1 do
begin
if not isPrime(n) then
Continue;
var val := n.ToString;
var valr := reverse(val);
var nr := valr.ToInteger;
if not isPrime(nr) then
Continue;
write(n: 4);
inc(row);
inc(count);
if row mod 10 = 0 then
writeln;
end;
writeln(#10#10, 'found ', count, ' primes');
Writeln('done...');
readln;
end.</lang>
{{out}}
<pre>working...
2 3 5 7 11 13 17 31 37 71
73 79 97 101 107 113 131 149 151 157
167 179 181 191 199 311 313 337 347 353
359 373 383 389
found 34 primes
done...</pre>
=={{header|F_Sharp|F#}}==
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