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A336477
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a(n) = 1 if a regular n-gon is constructible with ruler (or, more precisely, an unmarked straightedge) and compass, 0 otherwise.
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9
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1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0
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OFFSET
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1
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COMMENTS
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For all n >= 1, a(n) = 1 => A295297(n) = 0.
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LINKS
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FORMULA
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Multiplicative with a(2^e) = 1, and for odd primes p, a(p^e) = A209229(p-1) if e = 1, and 0 if e > 1. - Antti Karttunen, Jan 06 2023
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PROG
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(PARI)
A329697(n) = if(!bitand(n, n-1), 0, 1+A329697(n-(n/vecmax(factor(n)[, 1]))));
(PARI)
A209229(n) = (n && !bitand(n, n-1));
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CROSSREFS
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Characteristic function of A003401.
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KEYWORD
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nonn,mult
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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