Check if sum of first n primes is prime: Difference between revisions

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{{Draft task}}
{{Draft task}}


;Task:Check if sum of first '''n''' primes is prime, where '''n < 1,000'''
;Task:Check if sum of first '''n''' primes is prime, where '''n <= 20'''


<br><br>
<br><br>
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load "stdlib.ring"
load "stdlib.ring"
see "working..." + nl
see "working..." + nl
see "Sum of first n primes is prime:" + nl
see "Sum of first primes is prime:" + nl
num = 0
primSum = 0
primSum = 0


for n = 1 to 1000
for n = 1 to 10000
if isprime(n)
if isprime(n)
primSum += n
primSum += n
if isprime(primSum)
if isprime(primSum)
num++
see "n" + "(" + n + ") = " + primsum + " is prime" + nl
see "n" + "(" + num + ") = " + primsum + " is prime" + nl
ok
ok
ok
if num = 20
exit
ok
ok
next
next
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working...
working...
Sum of first primes is prime:
Sum of first primes is prime:
n(2) = 2 is prime
n(1) = 2 is prime
n(3) = 5 is prime
n(2) = 5 is prime
n(7) = 17 is prime
n(3) = 17 is prime
n(13) = 41 is prime
n(4) = 41 is prime
n(37) = 197 is prime
n(5) = 197 is prime
n(43) = 281 is prime
n(6) = 281 is prime
n(281) = 7699 is prime
n(7) = 7699 is prime
n(311) = 8893 is prime
n(8) = 8893 is prime
n(503) = 22039 is prime
n(9) = 22039 is prime
n(541) = 24133 is prime
n(10) = 24133 is prime
n(557) = 25237 is prime
n(11) = 25237 is prime
n(593) = 28697 is prime
n(12) = 28697 is prime
n(619) = 32353 is prime
n(13) = 32353 is prime
n(673) = 37561 is prime
n(14) = 37561 is prime
n(683) = 38921 is prime
n(15) = 38921 is prime
n(733) = 43201 is prime
n(16) = 43201 is prime
n(743) = 44683 is prime
n(17) = 44683 is prime
n(839) = 55837 is prime
n(18) = 55837 is prime
n(881) = 61027 is prime
n(19) = 61027 is prime
n(929) = 66463 is prime
n(20) = 66463 is prime
n(953) = 70241 is prime
done...
done...
</pre>
</pre>

Revision as of 07:36, 23 July 2021

Check if sum of first n primes is prime 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
Check if sum of first n primes is prime, where n <= 20



Ring

<lang ring> load "stdlib.ring" see "working..." + nl see "Sum of first primes is prime:" + nl num = 0 primSum = 0

for n = 1 to 10000

   if isprime(n)
      primSum += n
      if isprime(primSum)
         num++
         see "n" + "(" + num + ") = " + primsum + " is prime" + nl
      ok
   ok
   if num = 20
      exit
   ok

next

see "done..." + nl </lang>

Output:
working...
Sum of first primes is prime:
n(1) = 2 is prime
n(2) = 5 is prime
n(3) = 17 is prime
n(4) = 41 is prime
n(5) = 197 is prime
n(6) = 281 is prime
n(7) = 7699 is prime
n(8) = 8893 is prime
n(9) = 22039 is prime
n(10) = 24133 is prime
n(11) = 25237 is prime
n(12) = 28697 is prime
n(13) = 32353 is prime
n(14) = 37561 is prime
n(15) = 38921 is prime
n(16) = 43201 is prime
n(17) = 44683 is prime
n(18) = 55837 is prime
n(19) = 61027 is prime
n(20) = 66463 is prime
done...