Sum of two adjacent numbers are primes: Difference between revisions
Sum of two adjacent numbers are primes (view source)
Revision as of 13:05, 22 January 2022
, 2 years agoAdded Algol 68
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(Added Algol 68) |
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Show on this page the first 20 numbers and sum of two adjacent numbers which sum is prime.
=={{header|ALGOL 68}}==
{{libheader|ALGOL 68-primes}}
<lang algol68>BEGIN # find the first 20 primes which are n + ( n + 1 ) for some n #
PR read "primes.incl.a68" PR # include prime utilities #
[]BOOL prime = PRIMESIEVE 200; # should be enough primes #
INT p count := 0;
FOR n WHILE p count < 20 DO
INT n1 = n + 1;
INT p = n + n1;
IF prime[ p ] THEN
p count +:= 1;
print( ( whole( n, -2 ), " + ", whole( n1, -2 ), " = ", whole( p, -3 ), newline ) )
FI
OD
END</lang>
{{out}}
<pre>
1 + 2 = 3
2 + 3 = 5
3 + 4 = 7
5 + 6 = 11
6 + 7 = 13
8 + 9 = 17
9 + 10 = 19
11 + 12 = 23
14 + 15 = 29
15 + 16 = 31
18 + 19 = 37
20 + 21 = 41
21 + 22 = 43
23 + 24 = 47
26 + 27 = 53
29 + 30 = 59
30 + 31 = 61
33 + 34 = 67
35 + 36 = 71
36 + 37 = 73
</pre>
=={{header|C}}==
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