2023-07-18 13:51:12 -07:00
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func is_pseudoperfect(n, d = n.divisors.first(-1), s = d.sum, m = d.end) {
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2023-07-01 11:58:00 -04:00
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return false if (m < 0)
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while (d[m] > n) {
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s -= d[m--]
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}
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return true if (n == s)
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return true if (d[m] == n)
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__FUNC__(n-d[m], d, s-d[m], m-1) || __FUNC__(n, d, s-d[m], m-1)
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}
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func is_weird(n) {
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2023-07-18 13:51:12 -07:00
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(n.sigma > 2*n) && !is_pseudoperfect(n)
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2023-07-01 11:58:00 -04:00
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}
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var w = (1..Inf -> lazy.grep(is_weird).first(25))
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say "The first 25 weird numbers:\n#{w.join(' ')}"
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