Extreme primes
Definition
Write down the first prime number, add the next prime number and if it is prime, add it to the series and so on. These primes are called extreme primes
Task
Find and display the first 30 p extreme prime number on this page.
Ring
see "working..." + nl
limit = 2000
Primes = []
for n = 1 to limit
if isPrime(n)
add(Primes,n)
ok
next
sum = 0
row = 0
for n = 1 to len(Primes)
sum = sum + Primes[n]
if isPrime(sum)
row++
see "" + sum + " "
if row % 10 = 0
see nl
ok
ok
next
see "done..." + nl
func isPrime num
if (num <= 1) return 0 ok
if (num % 2 = 0 and num != 2) return 0 ok
for i = 3 to floor(num / 2) -1 step 2
if (num % i = 0) return 0 ok
next
return 1- Output:
working... 2 5 17 41 197 281 7699 8893 22039 24133 25237 28697 32353 37561 38921 43201 44683 55837 61027 66463 70241 86453 102001 109147 116533 119069 121631 129419 132059 263171 done...
Wren
This is very similar to the Prime numbers p for which the sum of primes less than or equal to p is prime task so I'm highly dubious about converting it to a separate draft task. I also found it at OEIS-A013918 though it doesn't appear to have a recognized name.
import "./math" for Int
import "./fmt" for Fmt
var primes = Int.primeSieve(300000)
var extremes = [2]
var sum = 2
var count = 1
for (p in primes.skip(1)) {
sum = sum + p
if (Int.isPrime(sum)) {
extremes.add(sum)
count = count + 1
if (count == 30) break
}
}
System.print("The first 30 extreme primes are:")
Fmt.tprint("$,7d ", extremes, 6)- Output:
The first 30 extreme primes are:
2 5 17 41 197 281
7,699 8,893 22,039 24,133 25,237 28,697
32,353 37,561 38,921 43,201 44,683 55,837
61,027 66,463 70,241 86,453 102,001 109,147
116,533 119,069 121,631 129,419 132,059 263,171