A091428 - OEIS

%I #11 Jan 11 2023 06:39:37

%S 1,3,4,5,7,11,12,13,15,17,19,20,21,23,28,29,31,33,35,37,39,41,43,44,

%T 47,51,52,53,55,57,59,60,61,65,67,68,69,71,73,76,77,79,83,84,85,87,89,

%U 91,92,93,95,97,101,103,105,107,109,111,113,115,116,119,123,124,127,129

%N Numbers k such that abs(A092673(k)) = 1.

%C The asymptotic density of this sequence is 5/Pi^2 = 0.506605... . - _Amiram Eldar_, Jan 11 2023

%H Amiram Eldar, <a href="/A091428/b091428.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Range[130], Abs[MoebiusMu[#] - If[EvenQ[#], MoebiusMu[#/2], 0]] == 1 &] (* _Amiram Eldar_, Jan 11 2023 *)

%Y Disjoint union of A056911 and A081770.

%Y Cf. A092673, A359592 (characteristic function).

%Y Distinct from A020486.

%K nonn

%O 1,2

%A _Jon Perry_, Mar 02 2004