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Duplicate of A067051
4

%I #30 Sep 08 2022 08:45:07

%S 2,8,18,32,49,50,72,98,128,162,169,196,200,242,288,338,361,392,441,

%T 450,512,578,648,676,722,784,800,882,961,968,1058,1152,1225,1250,1352,

%U 1369,1444,1458,1521,1568,1682,1764,1800,1849,1922,2048,2178,2312,2450,2592

%N Duplicate of A067051

%C Square terms are in A074216. Nonsquare terms appear to be A001105 except {0}. - _Michel Marcus_, Dec 26 2013

%C In the prime factorization of n, no odd prime has odd exponent, and 2 has odd exponent or at least one prime == 1 (mod 6) has exponent == 2 (mod 6). - _Robert Israel_, Dec 11 2015

%H Robert Israel, <a href="/A074629/b074629.txt">Table of n, a(n) for n = 1..10000</a>

%F A000203(n) mod 6 = 3.

%F {n: A084301(n) = 3 }. - _R. J. Mathar_, May 19 2020

%e n=32: sigma(32) = 63 = 6*10 + 3.

%p select(t -> numtheory:-sigma(t) mod 6 = 3, [$1..10000]); # _Robert Israel_, Dec 11 2015

%t Select[Range@ 2600, Mod[DivisorSigma[1, #], 6] == 3 &] (* _Michael De Vlieger_, Dec 10 2015 *)

%o (PARI) isok(n) = (sigma(n) % 6) == 3; \\ _Michel Marcus_, Dec 26 2013

%o (Magma) [n: n in [1..3*10^3] | (SumOfDivisors(n) mod 6) eq 3]; // _Vincenzo Librandi_, Dec 11 2015

%Y Cf. A000203, A072862, A074384, A074627, A074628, A074630.

%Y Appears to be the same sequence as A067051. - _Ralf Stephan_, Aug 18 2004

%K dead

%O 1,1

%A _Labos Elemer_, Aug 26 2002