Untouchable numbers: Difference between revisions
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(→{{header|REXX}}: changed the code to be more idiomatic, optimized the sigmaP function (aliquot function) for about a 5% improvement in speed, updated (correct) count of untouchable numbers for up to and including a million.) |
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=={{header|Julia}}== |
=={{header|Julia}}== |
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I can prove that the number to required to sieve to assure only untouchables for |
I can prove that the number to required to sieve to assure only untouchables for the interval 1:N is less than (N/2 - 1)^2, |
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but the |
but the 512,000,000 sieved below is just from doubling 1,000,000 and running the sieve until we get 150232 for the number |
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of untouchables under 1,000,000. |
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<lang julia>using Primes |
<lang julia>using Primes |
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end |
end |
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const maxtarget, sievelimit = |
const maxtarget, sievelimit = 1_000_000, 512_000_000 |
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const untouchables = ones(Bool, maxtarget) |
const untouchables = ones(Bool, maxtarget) |
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print(rpad(n, 5), i % 10 == 0 || i == 196 ? "\n" : "") |
print(rpad(n, 5), i % 10 == 0 || i == 196 ? "\n" : "") |
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end |
end |
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for N in [2000, 10, 100, 1000, 10_000, 100_000] |
for N in [2000, 10, 100, 1000, 10_000, 100_000, 1_000_000] |
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println("The count of untouchable numbers ≤ $N is: ", count(x -> untouchables[x], 1:N)) |
println("The count of untouchable numbers ≤ $N is: ", count(x -> untouchables[x], 1:N)) |
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end |
end |
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The count of untouchable numbers ≤ 10000 is: 1212 |
The count of untouchable numbers ≤ 10000 is: 1212 |
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The count of untouchable numbers ≤ 100000 is: 13863 |
The count of untouchable numbers ≤ 100000 is: 13863 |
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The count of untouchable numbers ≤ 1000000 is: 150232 |
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</pre> |
</pre> |
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