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A172335 Numbers n such that n and n+17 have same sum of divisors. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
REFERENCES
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.
LINKS
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].
MAPLE
with(numtheory):for n from 1 to 250000 do; if sigma(n) = sigma(n+17) then print(n); else fi ; od;
MATHEMATICA
Select[Range[10^5], DivisorSigma[1, #] == DivisorSigma[1, # + 17] &] (* Amiram Eldar, Aug 11 2019 *)
PROG
(Magma) [m:m in [1..250000]| SumOfDivisors(m) eq SumOfDivisors(m+17)]; // Marius A. Burtea, Aug 11 2019
CROSSREFS
Cf. A000203.
Sequence in context: A025379 A202279 A035702 * A217531 A158135 A092230
KEYWORD
nonn
AUTHOR
Michel Lagneau, Feb 01 2010
STATUS
approved

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Last modified April 18 11:52 EDT 2024. Contains 371779 sequences. (Running on oeis4.)