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A002975
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Primitive weird numbers.
(Formerly M5340)
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2
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70, 836, 4030, 5830, 7192, 7912, 9272, 10792, 17272, 45356, 73616, 83312, 91388, 113072, 243892, 254012, 338572, 343876, 388076, 519712, 539744, 555616, 682592, 786208, 1188256, 1229152, 1713592, 1901728, 2081824, 2189024, 3963968, 4128448
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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REFERENCES
| S. J. Benkoski and P. Erdos, On weird and pseudoperfect numbers, Math. Comp., 28 (1974), 617-623.
R. K. Guy, Unsolved Problems in Number Theory, B2.
R. Honsberger, Mathematical Gems, M.A.A., 1973, p. 113.
Problem E2308, Amer. Math. Monthly, 79 (1972), 774.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| Robert G. Wilson v, Table of n, a(n) for n = 1..57 . [From Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 04 2009]
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MATHEMATICA
| (* first do *) << Combinatorica` (* then *) fQ[n_] := Block[{d = Most@ Divisors@ n, l = 2^(DivisorSigma[0, n] - 1), i = 1}, i = 1; While[i < l && Plus @@ NthSubset[i, d] != n, i++ ]; i == l]; lst = {}; Do[m = n; If[ Mod[n, 6] != 0 && DivisorSigma[1, n] > 2 n && Union[ Mod[ n, Join[lst, {n + 1}]]][[1]] != 0 && fQ@n, AppendTo[lst, n]; Print@n], {n, 2, 42000000, 2}] [From Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 04 2009]
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CROSSREFS
| Cf. A006037.
Sequence in context: A027804 A177298 A006037 * A061170 A125114 A189413
Adjacent sequences: A002972 A002973 A002974 * A002976 A002977 A002978
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KEYWORD
| nonn,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| More terms from Jud McCranie (JudMcCranie(AT)ugaalum.uga.edu), Oct 21 2001
Added one more term. Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 04 2009
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