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A172335
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Numbers n such that n and n+17 have same sum of divisors.
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2
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142, 238, 418, 429, 598, 622, 2985, 3502, 16269, 22678, 23188, 27778, 38494, 46761, 48489, 62235, 74188, 98745, 110170, 120345, 129448, 151677, 187822, 190888, 194818, 205185, 223685, 235438, 246934, 249166
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OFFSET
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1,1
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REFERENCES
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M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 840.
J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 62, p. 22, Ellipses, Paris 2008.
W. Sierpiński, A Selection of Problems in the Theory of Numbers. Macmillan, NY, 1964, p. 110.
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LINKS
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M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
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MAPLE
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with(numtheory):for n from 1 to 250000 do; if sigma(n) = sigma(n+17) then print(n); else fi ; od;
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MATHEMATICA
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Select[Range[10^5], DivisorSigma[1, #] == DivisorSigma[1, # + 17] &] (* Amiram Eldar, Aug 11 2019 *)
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PROG
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(Magma) [m:m in [1..250000]| SumOfDivisors(m) eq SumOfDivisors(m+17)]; // Marius A. Burtea, Aug 11 2019
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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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