Sum of two adjacent numbers are primes
Show on this page the first 20 numbers and sum of two adjacent numbers which sum is prime.
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
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