Check if sum of first n primes is prime: Difference between revisions
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I deleted it because exists a similar '''Summarize primes''' task. |
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{{Draft task}} |
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<br>Gal Zsolt (CalmoSoft) |
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;Task:Check if sum of first '''n''' primes is prime, where '''n <= 20''' |
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<br><br> |
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=={{header|Julia}}== |
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<lang julia>using Primes |
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</lang> |
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The sum of the first 20 primes is |
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<lang julia>julia> sum(prime(i) for i in 1:20) |
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639 |
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</lang> |
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So, with a bit of experimentation, we find that to duplicate the Ring result we need to sum up to the first 160 primes, which then |
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gives us 20 prime results when we filter for a prime number as the sum: |
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<lang julia>julia> filter(isprime, accumulate(+, primes(prime(160)))) |
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20-element Vector{Int64}: |
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2 |
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5 |
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17 |
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41 |
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197 |
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281 |
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7699 |
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8893 |
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22039 |
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24133 |
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25237 |
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28697 |
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32353 |
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37561 |
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38921 |
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43201 |
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44683 |
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55837 |
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61027 |
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66463 |
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</lang> |
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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 "Sum of first primes is prime:" + nl |
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n = 0 |
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num = 0 |
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primSum = 0 |
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while true |
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n++ |
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if isprime(n) |
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primSum += n |
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if isprime(primSum) |
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num++ |
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see "n" + "(" + num + ") = " + primsum + " is prime" + nl |
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ok |
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ok |
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if num = 20 |
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exit |
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ok |
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end |
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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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Sum of first primes is prime: |
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n(1) = 2 is prime |
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n(2) = 5 is prime |
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n(3) = 17 is prime |
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n(4) = 41 is prime |
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n(5) = 197 is prime |
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n(6) = 281 is prime |
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n(7) = 7699 is prime |
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n(8) = 8893 is prime |
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n(9) = 22039 is prime |
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n(10) = 24133 is prime |
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n(11) = 25237 is prime |
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n(12) = 28697 is prime |
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n(13) = 32353 is prime |
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n(14) = 37561 is prime |
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n(15) = 38921 is prime |
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n(16) = 43201 is prime |
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n(17) = 44683 is prime |
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n(18) = 55837 is prime |
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n(19) = 61027 is prime |
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n(20) = 66463 is prime |
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done... |
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</pre> |
Latest revision as of 10:35, 23 July 2021
I deleted it because exists a similar Summarize primes task.
Gal Zsolt (CalmoSoft)