Perfect totient numbers: Difference between revisions
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Not a robot (talk | contribs) Add Modula-2 |
Added Algol 68 |
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<pre> |
<pre> |
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[3, 9, 15, 27, 39, 81, 111, 183, 243, 255, 327, 363, 471, 729, 2187, 2199, 3063, 4359, 4375, 5571] |
[3, 9, 15, 27, 39, 81, 111, 183, 243, 255, 327, 363, 471, 729, 2187, 2199, 3063, 4359, 4375, 5571] |
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</pre> |
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=={{header|ALGOL 68}}== |
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Not sure why 1 is excluded... |
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<lang algol68>BEGIN # find the first 20 perfect totient numbers # |
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# returns the number of integers k where 1 <= k <= n that are mutually prime to n # |
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PROC totient = ( INT n )INT: # algorithm from the second Go sample # |
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IF n < 3 THEN 1 |
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ELIF n = 3 THEN 2 |
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ELSE |
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INT result := n; |
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INT v := n; |
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INT i := 2; |
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WHILE i * i <= v DO |
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IF v MOD i = 0 THEN |
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WHILE v MOD i = 0 DO v OVERAB i OD; |
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result -:= result OVER i |
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FI; |
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IF i = 2 THEN |
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i := 1 |
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FI; |
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i +:= 2 |
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OD; |
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IF v > 1 THEN result -:= result OVER v FI; |
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result |
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FI # totient # ; |
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# find the first 20 perfect totient numbers # |
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INT p count := 0; |
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FOR i FROM 2 WHILE p count < 20 DO |
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INT t := totient( i ); |
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INT sum := t; |
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WHILE t /= 1 DO |
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t := totient( t ); |
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sum +:= t |
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OD; |
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IF sum = i THEN |
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# have a perfect totient # |
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p count +:= 1; |
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print( ( " ", whole( i, 0 ) ) ) |
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FI |
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OD; |
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print( ( newline ) ) |
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END</lang> |
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{{out}} |
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<pre> |
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3 9 15 27 39 81 111 183 243 255 327 363 471 729 2187 2199 3063 4359 4375 5571 |
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</pre> |
</pre> |
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