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A125496 Deficient cubes. 1
1, 8, 27, 64, 125, 343, 512, 729, 1331, 2197, 3375, 4096, 4913, 6859, 9261, 12167, 15625, 19683, 24389, 29791, 32768, 35937, 39304, 42875, 50653, 54872, 59319, 68921, 79507, 91125, 97336, 103823, 117649, 132651, 148877, 166375, 185193 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
MAPLE
with(numtheory): a:=proc(n) if sigma(n^3)<2*n^3 then n^3 else fi end: seq(a(n), n=1..70); # Emeric Deutsch, Jan 10 2007
isA005100 := proc(n) if numtheory[sigma](n) < 2*n then RETURN(true) ; else RETURN(false) ; fi ; end : for n from 1 to 100 do if isA005100(n^3) then printf("%d, ", n^3) ; fi ; od ; # R. J. Mathar, Jan 12 2007
MATHEMATICA
Select[Range[60]^3, DivisorSigma[1, #]<2#&] (* Harvey P. Dale, Feb 15 2014 *)
CROSSREFS
Intersection of A005100 (deficient numbers) and A000578 (cubes).
Sequence in context: A052048 A052064 A352049 * A030289 A111131 A111103
KEYWORD
nonn
AUTHOR
Tanya Khovanova, Dec 27 2006
EXTENSIONS
More terms from Emeric Deutsch, Jan 10 2007
More terms from R. J. Mathar, Jan 12 2007
STATUS
approved

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Last modified July 23 17:49 EDT 2024. Contains 374553 sequences. (Running on oeis4.)