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A246419 Numbers n such that n^6 - 2 is not squarefree. 0
10, 22, 50, 143, 204, 267, 311, 312, 423, 455, 461, 479, 506, 556, 579, 600, 649, 818, 845, 889, 987, 1008, 1104, 1108, 1134, 1178, 1258, 1273, 1333, 1343, 1416, 1423, 1467, 1537, 1610, 1637, 1712, 1756, 1779, 2001, 2005, 2045, 2065, 2066, 2104, 2166, 2205 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..47.

EXAMPLE

10^6 - 2 = 999998, which is divisible by 16129 = 127^2, so 10 is in the sequence.

11^6 - 2 = 1771559, which is prime, and 12^6 - 2 = 2985982 = 2 * 17 * 31 * 2833 (all prime), so neither of these numbers is in the sequence.

MAPLE

remove(t -> numtheory:-issqrfree(t^6-2), [$1..3000]); # Robert Israel, Aug 25 2014

MATHEMATICA

Select[Range[2000], MoebiusMu[#^6 - 2] == 0 &] (* Alonso del Arte, Aug 25 2014 *)

PROG

(Python) from sympy import factorint

[i for i in range(1, 1000) if max(list(factorint(i**6-2).values()))>1]

(PARI) isok(n) = ! issquarefree(n^6-2); \\ Michel Marcus, Oct 11 2014

(MAGMA) [n: n in [0..3000] | not IsSquarefree(n^6-2)]; // Vincenzo Librandi, Oct 16 2014

CROSSREFS

Cf. A005117, A013928.

Sequence in context: A079861 A014008 A219744 * A039315 A225708 A088871

Adjacent sequences:  A246416 A246417 A246418 * A246420 A246421 A246422

KEYWORD

nonn

AUTHOR

Mark E. Shoulson, Aug 25 2014

STATUS

approved

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Last modified May 21 15:00 EDT 2019. Contains 323443 sequences. (Running on oeis4.)