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A015810
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k is the first integer such that phi(k+n) | sigma(k)+n.
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0
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1, 1, 10, 1, 6, 1, 10, 1, 7, 16, 5, 1, 3, 2, 10, 1, 14, 1, 10
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OFFSET
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0,3
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COMMENTS
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a(20)=12, a(21)=98, a(22)=26, a(23)=1, a(24)=15, a(25)=8. - Jud McCranie, Jan 19 2020
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LINKS
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EXAMPLE
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For n=6, a(6)=10 because phi(10+6)=8 which divides sigma(10)+6=24, and k=10 is the smallest integer with that property. - Jud McCranie, Jan 19 2020
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PROG
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(PARI) a(n) = k=1; while ((sigma(k)+n) % eulerphi(k+n), k++); k; \\ Michel Marcus, Feb 03 2014
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CROSSREFS
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KEYWORD
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nonn,more,hard
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AUTHOR
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STATUS
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approved
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