Cousin primes
Cousin 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
- n and n+4 are cousin primes if they are primes.
Show the cousin primes for 1 < n < 1000
Ring
<lang ring> load "stdlib.ring"
see "working..." + nl see "cousin primes are:" + nl
ind = 0 row = 0 limit = 1000
for n = 1 to limit
if isprime(n) and isprime(n+4) row = row + 1 see "(" + n + ", " + (n+4) + ") " if row%5 = 0 see nl ok ok
next
see nl + "done..." + nl </lang>
- Output:
working... cousin primes are: (3, 7) (7, 11) (13, 17) (19, 23) (37, 41) (43, 47) (67, 71) (79, 83) (97, 101) (103, 107) (109, 113) (127, 131) (163, 167) (193, 197) (223, 227) (229, 233) (277, 281) (307, 311) (313, 317) (349, 353) (379, 383) (397, 401) (439, 443) (457, 461) (463, 467) (487, 491) (499, 503) (613, 617) (643, 647) (673, 677) (739, 743) (757, 761) (769, 773) (823, 827) (853, 857) (859, 863) (877, 881) (883, 887) (907, 911) (937, 941) (967, 971) done...