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

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{{Draft task}}
 
;Task:Check if sum of first '''n''' primes is prime, where '''n <= 1,00020'''
 
<br><br>
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load "stdlib.ring"
see "working..." + nl
see "Sum of first n primes is prime:" + nl
num = 0
primSum = 0
 
for n = 1 to 100010000
if isprime(n)
primSum += n
if isprime(primSum)
num++
see "n" + "(" + nnum + ") = " + primsum + " is prime" + nl
ok
ok
if num = 20
exit
ok
next
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working...
Sum of first primes is prime:
n(21) = 2 is prime
n(32) = 5 is prime
n(73) = 17 is prime
n(134) = 41 is prime
n(375) = 197 is prime
n(436) = 281 is prime
n(2817) = 7699 is prime
n(3118) = 8893 is prime
n(5039) = 22039 is prime
n(54110) = 24133 is prime
n(55711) = 25237 is prime
n(59312) = 28697 is prime
n(61913) = 32353 is prime
n(67314) = 37561 is prime
n(68315) = 38921 is prime
n(73316) = 43201 is prime
n(74317) = 44683 is prime
n(83918) = 55837 is prime
n(88119) = 61027 is prime
n(92920) = 66463 is prime
n(953) = 70241 is prime
done...
</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...