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A125499
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Deficient even numbers.
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5
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2, 4, 8, 10, 14, 16, 22, 26, 32, 34, 38, 44, 46, 50, 52, 58, 62, 64, 68, 74, 76, 82, 86, 92, 94, 98, 106, 110, 116, 118, 122, 124, 128, 130, 134, 136, 142, 146, 148, 152, 154, 158, 164, 166, 170, 172, 178, 182, 184, 188, 190, 194, 202, 206, 212, 214, 218, 226, 230
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OFFSET
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1,1
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LINKS
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EXAMPLE
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22 is in the sequence because it is even and its sum of divisors 1+2+11+22=36 is less than 2*22.
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MAPLE
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with(numtheory): a:=proc(n) if sigma(n)<2*n and n mod 2 = 0 then n else fi end: seq(a(n), n=1..290); # Emeric Deutsch, Jan 01 2007
isA005100 := proc(n) if numtheory[sigma](n) < 2*n then RETURN(true) ; else RETURN(false) ; fi ; end : for n from 2 to 800 by 2 do if isA005100(n) then printf("%d, ", n) ; fi ; od ; # R. J. Mathar, Jan 07 2007
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MATHEMATICA
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Select[Range[2, 250, 2], DivisorSigma[1, #]<2#&] (* Harvey P. Dale, Apr 04 2023 *)
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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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