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A194578
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Numbers n such that the sum of the first k divisors of n^2+1 is equal to n for some k.
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0
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1, 3, 43, 68, 93, 228, 612, 1903, 32292, 44868, 252072, 36564198, 55862807, 134735264
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OFFSET
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1,2
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COMMENTS
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No further at least up to 10^7.
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LINKS
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EXAMPLE
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The divisors of 43^2 + 1 are {1, 2, 5, 10, 25, 37, 50, 74, 185, 370, 925, 1850} and 1+2+5+10 + 25 = 43, hence 43 is in the list.
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MATHEMATICA
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Select[Range[10000000], MemberQ[Accumulate[Divisors[#^2+1]], #]&]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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