Perfect numbers: Difference between revisions
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=={{header|PARI/GP}}== |
=={{header|PARI/GP}}== |
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Uses built-in method. Faster tests would use the LL test for evens and myriad results on OPNs otherwise. |
Uses built-in method. Faster tests would use the LL test for evens and myriad results on OPNs otherwise. |
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<lang>isPerfect(n)=sigma(n,-1)==2</lang> |
<lang parigp>isPerfect(n)=sigma(n,-1)==2</lang> |
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Show perfect numbers |
Show perfect numbers |
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<lang>forprime(p=2, 2281, |
<lang parigp>forprime(p=2, 2281, |
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if(isprime(2^p-1), |
if(isprime(2^p-1), |
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print(p"\t",(2^p-1)*2^(p-1))))</lang> |
print(p"\t",(2^p-1)*2^(p-1))))</lang> |
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Faster with Lucas-Lehmer test |
Faster with Lucas-Lehmer test |
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<lang>p=2;n=3;n1=2; |
<lang parigp>p=2;n=3;n1=2; |
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while(p<2281, |
while(p<2281, |
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if(isprime(p), |
if(isprime(p), |
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</lang> |
</lang> |
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output |
output |
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< |
<pre>(2^2-1)2^(2-1)= 6 |
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(2^3-1)2^(3-1)= 28 |
(2^3-1)2^(3-1)= 28 |
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(2^5-1)2^(5-1)= 496 |
(2^5-1)2^(5-1)= 496 |
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(2^31-1)2^(31-1)= 2305843008139952128 |
(2^31-1)2^(31-1)= 2305843008139952128 |
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(2^61-1)2^(61-1)= 2658455991569831744654692615953842176 |
(2^61-1)2^(61-1)= 2658455991569831744654692615953842176 |
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(2^89-1)2^(89-1)= 191561942608236107294793378084303638130997321548169216</ |
(2^89-1)2^(89-1)= 191561942608236107294793378084303638130997321548169216</pre> |
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=={{header|Perl}}== |
=={{header|Perl}}== |
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