Numbers whose binary and ternary digit sums are prime: Difference between revisions
Numbers whose binary and ternary digit sums are prime (view source)
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199</pre>
=={{header|Delphi}}==
{{works with|Delphi|6.0}}
{{libheader|SysUtils,StdCtrls}}
<syntaxhighlight lang="Delphi">
function IsPrime(N: int64): boolean;
{Fast, optimised prime test}
var I,Stop: int64;
begin
if (N = 2) or (N=3) then Result:=true
else if (n <= 1) or ((n mod 2) = 0) or ((n mod 3) = 0) then Result:= false
else
begin
I:=5;
Stop:=Trunc(sqrt(N+0.0));
Result:=False;
while I<=Stop do
begin
if ((N mod I) = 0) or ((N mod (I + 2)) = 0) then exit;
Inc(I,6);
end;
Result:=True;
end;
end;
function SumDigitsByBase(N,Base: integer): integer;
{Sum all digits of N in the specified B}
var I: integer;
begin
Result:=0;
repeat
begin
I:=N mod Base;
Result:=Result+I;
N:=N div Base;
end
until N = 0;
end;
function IsBinaryTernaryPrime(N: integer): boolean;
{Test if sums of binary and ternary digits is prime}
var Sum2,Sum3: integer;
begin
Result:=IsPrime(SumDigitsByBase(N,2)) and
IsPrime(SumDigitsByBase(N,3));
end;
procedure ShowBinaryTernaryPrimes(Memo: TMemo);
{Show the Binary-Ternary sum primes of first 200 values}
var I,Cnt: integer;
var S: string;
begin
S:=''; Cnt:=0;
for I:=0 to 200-1 do
if IsBinaryTernaryPrime(I) then
begin
Inc(Cnt);
S:=S+Format('%8D',[I]);
If (Cnt mod 5)=0 then S:=S+CRLF;
end;
Memo.Lines.Add(S);
Memo.Lines.Add('Count= '+IntToStr(Cnt));
end;
</syntaxhighlight>
{{out}}
<pre>
5 6 7 10 11
12 13 17 18 19
21 25 28 31 33
35 36 37 41 47
49 55 59 61 65
67 69 73 79 82
84 87 91 93 97
103 107 109 115 117
121 127 129 131 133
137 143 145 151 155
157 162 167 171 173
179 181 185 191 193
199
Count= 61
Elapsed Time: 3.322 ms.
</pre>
=={{header|F_Sharp|F#}}==
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