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A345058
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Number of distinct k > 0 for which A011772(k) = n.
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3
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1, 2, 1, 3, 2, 2, 2, 7, 4, 2, 2, 4, 4, 3, 1, 5, 4, 4, 3, 7, 2, 3, 2, 7, 6, 4, 3, 3, 4, 7, 4, 13, 3, 4, 2, 4, 6, 3, 4, 7, 6, 3, 4, 7, 1, 5, 2, 7, 11, 6, 2, 7, 4, 5, 2, 11, 3, 4, 2, 7, 8, 5, 5, 7, 2, 3, 4, 4, 5, 3, 4, 13, 9, 6, 6, 9, 2, 4, 4, 8, 15, 6, 2, 11, 3, 3, 3, 7, 6, 3, 1, 5, 4, 7, 3, 13, 10, 11, 7, 6, 6, 5, 4, 8, 2
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OFFSET
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1,2
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COMMENTS
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Question: Are there any numbers n other than 1, 3, 15, 45, 91 for which a(n) = 1?
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LINKS
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FORMULA
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EXAMPLE
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PROG
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(PARI)
A011772(n) = { if(n==1, return(1)); my(f=factor(if(n%2, n, 2*n)), step=vecmax(vector(#f~, i, f[i, 1]^f[i, 2]))); forstep(m=step, 2*n, step, if(m*(m-1)/2%n==0, return(m-1)); if(m*(m+1)/2%n==0, return(m))); }; \\ From A011772
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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