Sum of primes in odd positions is prime: Difference between revisions
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823 26879
done...
</pre>
=={{header|Wren}}==
{{libheader|Wren-math}}
{{libheader|Wren-trait}}
{{libheader|Wren-fmt}}
<lang ecmascript>import "/math" for Int
import "/trait" for Indexed
import "/fmt" for Fmt
var primes = Int.primeSieve(999)
var sum = 0
System.print(" i p[i] Σp[i]")
System.print("----------------")
for (se in Indexed.new(primes, 2)) {
sum = sum + se.value
if (Int.isPrime(sum)) Fmt.print("$3d $3d $,6d", se.index + 1, se.value, sum)
}</lang>
{{out}}
<pre>
i p[i] Σp[i]
----------------
1 2 2
3 5 7
11 31 89
27 103 659
35 149 1,181
67 331 5,021
91 467 9,923
95 499 10,909
99 523 11,941
119 653 17,959
143 823 26,879
</pre>
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Revision as of 14:24, 1 September 2021
- Task
Let p(i) be a sequence of prime numbers.
Consider the p(1),p(3),p(5), ... ,p(i), for each p(i) < 1,000 and i is odd.
Let sum be summarize of these primes.
If sum is prime then print p(i) and sum
Factor
<lang factor>USING: assocs assocs.extras kernel math.primes math.statistics prettyprint sequences.extras ;
1000 primes-upto <evens> dup cum-sum zip [ prime? ] filter-values .</lang>
- Output:
{ { 2 2 } { 5 7 } { 31 89 } { 103 659 } { 149 1181 } { 331 5021 } { 467 9923 } { 499 10909 } { 523 11941 } { 653 17959 } { 823 26879 } }
Ring
<lang ring> load "stdlib.ring" see "working..." + nl see "p" + " sum" + nl
nr = 0 sum = 0 limit = 1000
for n = 2 to limit
if isprime(n) nr++ if nr%2 = 1 sum += n if isprime(sum) see "" + n + " " + sum + nl ok ok ok
next
see "done..." + nl </lang>
- Output:
working... p sum 2 2 5 7 31 89 103 659 149 1181 331 5021 467 9923 499 10909 523 11941 653 17959 823 26879 done...
Wren
<lang ecmascript>import "/math" for Int import "/trait" for Indexed import "/fmt" for Fmt
var primes = Int.primeSieve(999) var sum = 0 System.print(" i p[i] Σp[i]") System.print("----------------") for (se in Indexed.new(primes, 2)) {
sum = sum + se.value if (Int.isPrime(sum)) Fmt.print("$3d $3d $,6d", se.index + 1, se.value, sum)
}</lang>
- Output:
i p[i] Σp[i] ---------------- 1 2 2 3 5 7 11 31 89 27 103 659 35 149 1,181 67 331 5,021 91 467 9,923 95 499 10,909 99 523 11,941 119 653 17,959 143 823 26,879