Pairs with common factors: Difference between revisions
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Here, <code>p.</code> calculates a polynomial (1 + (-x)/2 + (x^2)/2 in this example), <code>5&p:</code> is euler's totient function, <code>@{:</code> modifies the polynomial to only operate on the final element of a sequence, <code>+/</code> is sum and <code>+/\</code> is running sum, and <code>1+i.n</code> is the sequence of numbers 1 through n. |
Here, <code>p.</code> calculates a polynomial (1 + (-x)/2 + (x^2)/2 in this example), <code>5&p:</code> is euler's totient function, <code>@{:</code> modifies the polynomial to only operate on the final element of a sequence, <code>+/</code> is sum and <code>+/\</code> is running sum, and <code>1+i.n</code> is the sequence of numbers 1 through n. |
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=={{header|Julia}}== |
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<lang ruby>using Formatting |
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using Primes |
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pcf(n) = n * (n - 1) ÷ 2 + 1 - sum(totient, 1:n) |
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foreach(p -> print(rpad(p[2], 5), p[1] % 20 == 0 ? "\n" : ""), pairs(map(pcf, 1:100))) |
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for expo in 0:6 |
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println("The ", format(10^expo, commas = true), "th pair with common factors count is ", |
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format(pcf(10^expo), commas = true)) |
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end |
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</lang{{out}} |
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<pre> |
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0 0 0 1 1 4 4 7 9 14 14 21 21 28 34 41 41 52 52 63 |
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71 82 82 97 101 114 122 137 137 158 158 173 185 202 212 235 235 254 268 291 |
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291 320 320 343 363 386 386 417 423 452 470 497 497 532 546 577 597 626 626 669 |
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669 700 726 757 773 818 818 853 877 922 922 969 969 1006 1040 1079 1095 1148 1148 1195 |
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1221 1262 1262 1321 1341 1384 1414 1461 1461 1526 1544 1591 1623 1670 1692 1755 1755 1810 1848 1907 |
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The 1th pair with common factors count is 0 |
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The 10th pair with common factors count is 14 |
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The 100th pair with common factors count is 1,907 |
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The 1,000th pair with common factors count is 195,309 |
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The 10,000th pair with common factors count is 19,597,515 |
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The 100,000th pair with common factors count is 1,960,299,247 |
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The 1,000,000th pair with common factors count is 196,035,947,609 |
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</pre> |
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=={{header|Phix}}== |
=={{header|Phix}}== |