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

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n = 173 => n^3 + 2 = 5177719
n = 173 => n^3 + 2 = 5177719
n = 189 => n^3 + 2 = 6751271</pre>
n = 189 => n^3 + 2 = 6751271</pre>

=={{header|COBOL}}==
<lang cobol> IDENTIFICATION DIVISION.
PROGRAM-ID. N3-PLUS-2-PRIMES.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 VARIABLES.
03 N PIC 9(3).
03 N3PLUS2 PIC 9(7).
03 DIVISOR PIC 9(4).
03 DIV-SQ PIC 9(8).
03 DIV-CHECK PIC 9(4)V9(4).
03 FILLER REDEFINES DIV-CHECK.
05 FILLER PIC 9(4).
05 FILLER PIC 9(4).
88 DIVISIBLE VALUE ZERO.
03 FILLER REDEFINES N3PLUS2.
05 FILLER PIC 9(6).
05 FILLER PIC 9.
88 EVEN VALUE 0, 2, 4, 6, 8.
03 PRIME-FLAG PIC X.
88 PRIME VALUE '*'.
01 FORMAT.
03 FILLER PIC X(4) VALUE "N = ".
03 N-OUT PIC ZZ9.
03 FILLER PIC X(17) VALUE " => N ** 3 + 2 = ".
03 N3PLUS2-OUT PIC Z(6)9.
PROCEDURE DIVISION.
BEGIN.
PERFORM TRY-N VARYING N FROM 1 BY 1
UNTIL N IS GREATER THAN 200.
STOP RUN.
TRY-N.
COMPUTE N3PLUS2 = N ** 3 + 2.
PERFORM CHECK-PRIME.
IF PRIME,
MOVE N TO N-OUT,
MOVE N3PLUS2 TO N3PLUS2-OUT,
DISPLAY FORMAT.
CHECK-PRIME SECTION.
BEGIN.
MOVE SPACE TO PRIME-FLAG.
IF N3PLUS2 IS LESS THAN 5, GO TO TRIVIAL.
IF EVEN, GO TO CHECK-PRIME-DONE.
DIVIDE N3PLUS2 BY 3 GIVING DIV-CHECK.
IF DIVISIBLE, GO TO CHECK-PRIME-DONE.
MOVE ZERO TO DIV-SQ.
MOVE 5 TO DIVISOR.
MOVE '*' TO PRIME-FLAG.
PERFORM CHECK-DIVISOR
UNTIL NOT PRIME OR DIV-SQ IS GREATER THAN N3PLUS2.
GO TO CHECK-PRIME-DONE.
CHECK-DIVISOR.
MULTIPLY DIVISOR BY DIVISOR GIVING DIV-SQ.
DIVIDE N3PLUS2 BY DIVISOR GIVING DIV-CHECK.
IF DIVISIBLE, MOVE SPACE TO PRIME-FLAG.
ADD 2 TO DIVISOR.
DIVIDE N3PLUS2 BY DIVISOR GIVING DIV-CHECK.
IF DIVISIBLE, MOVE SPACE TO PRIME-FLAG.
ADD 4 TO DIVISOR.
TRIVIAL.
IF N3PLUS2 IS EQUAL TO 2 OR EQUAL TO 3,
MOVE '*' TO PRIME-FLAG.
CHECK-PRIME-DONE.
EXIT.</lang>
{{out}}
<pre>N = 1 => N ** 3 + 2 = 3
N = 3 => N ** 3 + 2 = 29
N = 5 => N ** 3 + 2 = 127
N = 29 => N ** 3 + 2 = 24391
N = 45 => N ** 3 + 2 = 91127
N = 63 => N ** 3 + 2 = 250049
N = 65 => N ** 3 + 2 = 274627
N = 69 => N ** 3 + 2 = 328511
N = 71 => N ** 3 + 2 = 357913
N = 83 => N ** 3 + 2 = 571789
N = 105 => N ** 3 + 2 = 1157627
N = 113 => N ** 3 + 2 = 1442899
N = 123 => N ** 3 + 2 = 1860869
N = 129 => N ** 3 + 2 = 2146691
N = 143 => N ** 3 + 2 = 2924209
N = 153 => N ** 3 + 2 = 3581579
N = 171 => N ** 3 + 2 = 5000213
N = 173 => N ** 3 + 2 = 5177719
N = 189 => N ** 3 + 2 = 6751271</pre>


=={{header|Cowgol}}==
=={{header|Cowgol}}==
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