Safe and Sophie Germain primes: Difference between revisions
(added already done Safe_primes_and_unsafe_primes link) |
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1499 |
1499 |
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</pre> |
</pre> |
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=={{header|Julia}}== |
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<lang julia>using Primes |
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for (i, p) in enumerate(filter(x -> isprime(2x + 1), primes(1500))) |
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print(lpad(p, 5), i % 10 == 0 ? "\n" : "") |
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end |
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</lang>{{out}} |
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<pre> |
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2 3 5 11 23 29 41 53 83 89 |
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113 131 173 179 191 233 239 251 281 293 |
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359 419 431 443 491 509 593 641 653 659 |
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683 719 743 761 809 911 953 1013 1019 1031 |
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1049 1103 1223 1229 1289 1409 1439 1451 1481 1499 |
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</pre> |
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=={{header|XPL0}}== |
=={{header|XPL0}}== |
Revision as of 09:44, 10 December 2021
A prime number p is Sophie Germain prime if 2p + 1 is also prime.
- See the same at Safe_primes_and_unsafe_primes
The number 2p + 1 associated with a Sophie Germain prime is called a safe prime.
- Task
Generate the first 50 Sophie Germain prime numbers.
jq
Works with gojq, the Go implementation of jq
See e.g. #Find_adjacent_primes_which_differ_by_a_square_integer#jq for suitable implementions of `is_prime/0` and `primes/0` as used here. <lang jq>limit(50; primes | select(2*. + 1|is_prime))</lang>
- Output:
2 3 5 ... 1451 1481 1499
Julia
<lang julia>using Primes
for (i, p) in enumerate(filter(x -> isprime(2x + 1), primes(1500)))
print(lpad(p, 5), i % 10 == 0 ? "\n" : "")
end
</lang>
- Output:
2 3 5 11 23 29 41 53 83 89 113 131 173 179 191 233 239 251 281 293 359 419 431 443 491 509 593 641 653 659 683 719 743 761 809 911 953 1013 1019 1031 1049 1103 1223 1229 1289 1409 1439 1451 1481 1499
XPL0
<lang XPL0>func IsPrime(N); \Return 'true' if N is a prime number int N, I; [for I:= 2 to sqrt(N) do
if rem(N/I) = 0 then return false;
return true; ];
int N, Count; [N:= 2; Count:= 0; repeat if IsPrime(N) & IsPrime(2*N+1) then
[IntOut(0, N); ChOut(0, 9\tab\); Count:= Count+1; if rem(Count/10) = 0 then CrLf(0); ]; N:= N+1;
until Count >= 50; ]</lang>
- Output:
2 3 5 11 23 29 41 53 83 89 113 131 173 179 191 233 239 251 281 293 359 419 431 443 491 509 593 641 653 659 683 719 743 761 809 911 953 1013 1019 1031 1049 1103 1223 1229 1289 1409 1439 1451 1481 1499