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A007412
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The noncubes: n + [ (n + [ n^{1/3} ])^{1/3} ].
(Formerly M0493)
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10
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2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Seems to be numbers n for which order of torsion subgroup t of the elliptic curve y^2=x^3-n is t=1. [From Artur Jasinski (grafix(AT)csl.pl), Jun 30 2010]
A010057(a(n)) = 0. [Reinhard Zumkeller, Oct 22 2011]
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REFERENCES
| A. J. dos Reis and D. M. Silberger, Generating nonpowers by formula, Math. Mag., 63 (1990), 53-55.
J. Roberts, Lure of the Integers, Math. Assoc. America, 1992, p. 27911
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
Gebel J., Integer points on Mordell curves [From Artur Jasinski (grafix(AT)csl.pl), Jun 30 2010]
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FORMULA
| a(n) = n + A048766(n + A048766(n)). [Reinhard Zumkeller, Oct 22 2011]
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MATHEMATICA
| With[{upto=58}, Complement[Range[upto], Range[Ceiling[Power[upto, (3)^-1]]]^3]] (* From Harvey P. Dale, Nov 09 2011 *)
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PROG
| (Haskell)
a007412 n = n + a048766 (n + a048766 n) -- Reinhard Zumkeller, Oct 22 2011
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CROSSREFS
| Cf. A000578 (complement), A000037 (nonsquares).
Sequence in context: A089657 A004727 A102352 * A096432 A138302 A183220
Adjacent sequences: A007409 A007410 A007411 * A007413 A007414 A007415
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KEYWORD
| nonn,easy,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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