Sequence: smallest number with exactly n divisors: Difference between revisions
Sequence: smallest number with exactly n divisors (view source)
Revision as of 14:26, 15 May 2021
, 3 years ago→{{header|Sidef}}: added a more efficient solution
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(→{{header|Sidef}}: added a more efficient solution) |
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[1, 2, 4, 6, 16, 12, 64, 24, 36, 48, 1024, 60, 4096, 192, 144]
</pre>
More efficient solution:
<lang ruby>func n_divisors(threshold, least_solution = Inf, k = 1, max_a = Inf, solutions = 1, n = 1) {
if (solutions == threshold) {
return n
}
if (solutions > threshold) {
return least_solution
}
var p = k.prime
for a in (1 .. max_a) {
n *= p
break if (n > least_solution)
least_solution = __FUNC__(threshold, least_solution, k+1, a, solutions * (a + 1), n)
}
return least_solution
}
say n_divisors(60) #=> 5040
say n_divisors(1000) #=> 810810000</lang>
=={{header|Swift}}==
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