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A109760
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Composite n such that binomial(5*n,n) == 5^n (mod n).
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2
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4, 365, 400, 685, 3200, 6400, 12550, 12800, 16525, 25600, 51200, 225125, 70463125, 271094125, 431434441
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OFFSET
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1,1
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COMMENTS
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No other terms below 10^9.
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LINKS
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EXAMPLE
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4 is a term because binomial(5*4, 4) = 4845, 5^4 = 625 and 4845 mod 4 = 625 mod 4 = 1.
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MATHEMATICA
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Do[If[ !PrimeQ[n], If[Mod[Binomial[5*n, n], n] == Mod[5^n, n], Print[n]]], {n, 1, 50000}]
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CROSSREFS
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KEYWORD
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hard,more,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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