Sum of two adjacent numbers are primes
Sum of two adjacent numbers are primes 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
Show on this page the first 20 numbers and sum of two adjacent numbers which sum is prime.
Ring
<lang ring> load "stdlibcore.ring" see "working..." + nl n = 0 num = 0
while true
n++ sum = 2*n+1 if isprime(sum) num++ if num < 21 ? "n = " + n + " sum= " + sum else exit ok ok
end
see "done..." + nl </lang>
- Output:
working... n = 1 sum= 3 n = 2 sum= 5 n = 3 sum= 7 n = 5 sum= 11 n = 6 sum= 13 n = 8 sum= 17 n = 9 sum= 19 n = 11 sum= 23 n = 14 sum= 29 n = 15 sum= 31 n = 18 sum= 37 n = 20 sum= 41 n = 21 sum= 43 n = 23 sum= 47 n = 26 sum= 53 n = 29 sum= 59 n = 30 sum= 61 n = 33 sum= 67 n = 35 sum= 71 n = 36 sum= 73 done...
XPL0
<lang XPL0> include xpllib; int N, Num, Sum; [Text(0, "Working...^M^J"); N:= 0; Num:= 0; while true do
[N:= N+1; Sum:= 2*N + 1; if IsPrime(Sum) then [Num:= Num+1; if Num < 21 then [Text(0,"N = "); IntOut(0,N); Text(0," Sum = "); IntOut(0,Sum); CrLf(0)] else exit ] ];
Text(0, "Done...^M^J"); ]</lang>
- Output:
Working... N = 1 Sum = 3 N = 2 Sum = 5 N = 3 Sum = 7 N = 5 Sum = 11 N = 6 Sum = 13 N = 8 Sum = 17 N = 9 Sum = 19 N = 11 Sum = 23 N = 14 Sum = 29 N = 15 Sum = 31 N = 18 Sum = 37 N = 20 Sum = 41 N = 21 Sum = 43 N = 23 Sum = 47 N = 26 Sum = 53 N = 29 Sum = 59 N = 30 Sum = 61 N = 33 Sum = 67 N = 35 Sum = 71 N = 36 Sum = 73