Find prime numbers of the form n*n*n+2: Difference between revisions

=={{header|ALGOL 68}}==

<lang algol68>BEGIN # Find n such that n^3 + 2 is a prime for n < 200 #

FOR n TO 199 DO

INT candidate = ( n * n * n ) + 2;

# there will only be 199 candidates, so a primality check by trial #

# division should be OK #

BOOL is prime := TRUE;

FOR f FROM 2 TO ENTIER sqrt( candidate )

WHILE is prime := candidate MOD f /= 0

DO SKIP OD;

IF is prime THEN

# n^3 + 2 is prime #

print( ( whole( n, -4 ), ": ", whole( candidate, -8 ), newline ) )

FI

OD

END</lang>

{{out}}

<pre>

1: 3

3: 29

5: 127

29: 24391

45: 91127

63: 250049

65: 274627

69: 328511

71: 357913

83: 571789

105: 1157627

113: 1442899

123: 1860869

129: 2146691

143: 2924209

153: 3581579

171: 5000213

173: 5177719

189: 6751271

</pre>