Special divisors: Difference between revisions
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Numbers n such that reverse(d) divides reverse(n) for all divisors d of n, where '''n < 200''' |
Numbers n such that reverse(d) divides reverse(n) for all divisors d of n, where '''n < 200''' |
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<br><br> |
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=={{header|Julia}}== |
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<lang julia>using Primes |
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function divisors(n) |
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f = [one(n)] |
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for (p,e) in factor(n) |
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f = reduce(vcat, [f*p^j for j in 1:e], init=f) |
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end |
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return f[1:end-1] |
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end |
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function isspecialdivisor(n)::Bool |
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isprime(n) && return true |
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nreverse = evalpoly(10, reverse(digits(n))) |
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for d in divisors(n) |
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dreverse = evalpoly(10, reverse(digits(d))) |
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!(nreverse ÷ dreverse ≈ nreverse / dreverse) && return false |
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end |
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return true |
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end |
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const specials = filter(isspecialdivisor, 1:200) |
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foreach(p -> print(rpad(p[2], 4), p[1] % 18 == 0 ? "\n" : ""), enumerate(specials)) |
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</lang>{{out}} |
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<pre> |
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1 2 3 4 5 6 7 8 9 11 13 17 19 22 23 26 27 29 |
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31 33 37 39 41 43 44 46 47 53 55 59 61 62 66 67 69 71 |
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73 77 79 82 83 86 88 89 93 97 99 101 103 107 109 113 121 127 |
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131 137 139 143 149 151 157 163 167 169 173 179 181 187 191 193 197 199 |
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</pre> |
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=={{header|Phix}}== |
=={{header|Phix}}== |
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<!--<lang Phix>--> |
<!--<lang Phix>--> |
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