Special neighbor primes: Difference between revisions
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{{Draft task}} |
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;Task:Let ('''p<sub>1</sub>''', '''p<sub>2</sub>''') are neighbourprimes. Find and show here in base ten '''p<sub>1</sub> + p<sub>2</sub> - 1''' where '''p<sub>1</sub>, p<sub>2</sub> < 100'''. |
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<br><br> |
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=={{header|Ring}}== |
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<lang ring> |
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load "stdlib.ring" |
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see "working..." + nl |
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see "Special neighbour primes are:" + nl |
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row = 0 |
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oldPrime = 2 |
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for n = 3 to 100 |
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if isprime(n) and isprime(oldPrime) |
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sum = oldPrime + n - 1 |
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if isprime(sum) |
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row++ |
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see "" + oldPrime + "," + n + " => " + sum + nl |
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ok |
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oldPrime = n |
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ok |
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next |
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see "Found " + row + " special neighbour primes" |
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see "done..." + nl |
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</lang> |
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{{out}} |
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<pre> |
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working... |
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Special twin primes are: |
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3,5 => 7 |
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5,7 => 11 |
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7,11 => 17 |
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11,13 => 23 |
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13,17 => 29 |
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19,23 => 41 |
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29,31 => 59 |
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31,37 => 67 |
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41,43 => 83 |
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43,47 => 89 |
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61,67 => 127 |
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67,71 => 137 |
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73,79 => 151 |
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Found 13 special twin primesdone... |
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</pre> |
Revision as of 04:54, 6 August 2021
Special neighbor primes is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.
- Task
- Let (p1, p2) are neighbourprimes. Find and show here in base ten p1 + p2 - 1 where p1, p2 < 100.
Ring
<lang ring> load "stdlib.ring"
see "working..." + nl see "Special neighbour primes are:" + nl row = 0 oldPrime = 2
for n = 3 to 100
if isprime(n) and isprime(oldPrime) sum = oldPrime + n - 1 if isprime(sum) row++ see "" + oldPrime + "," + n + " => " + sum + nl ok oldPrime = n ok
next
see "Found " + row + " special neighbour primes" see "done..." + nl </lang>
- Output:
working... Special twin primes are: 3,5 => 7 5,7 => 11 7,11 => 17 11,13 => 23 13,17 => 29 19,23 => 41 29,31 => 59 31,37 => 67 41,43 => 83 43,47 => 89 61,67 => 127 67,71 => 137 73,79 => 151 Found 13 special twin primesdone...