A125496 Deficient cubes.

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

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

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

Adjacent sequences: A125493 A125494 A125495 * A125497 A125498 A125499

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