OFFSET
1,2
COMMENTS
Liouville function lambda(n) (A008836) is positive.
From Peter Munn, Jan 16 2020: (Start)
The sequence is closed under the commutative binary operation A059897(.,.). As integers are self-inverse under A059897, it forms a subgroup of the positive integers considered as a group under A059897.
This sequence is the intersection of A000379 and A056911, which are also subgroups of the positive integers under A059897.
(End)
The asymptotic density of this sequence is 2/Pi^2 (A185197). - Amiram Eldar, Oct 06 2020
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
H. Gupta, A formula for L(n), J. Indian Math. Soc., 7 (1943), 68-71. [Annotated scanned copy]
MATHEMATICA
f[n_]:=Last/@FactorInteger[n]=={1, 1}&&FactorInteger[n][[1, 1]]>2; a=6; lst={1}; Do[If[f[n], AppendTo[lst, n]], {n, 6!}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 23 2009 *)
Select[Range[1, 303, 2], MoebiusMu[#] == 1 &] (* Amiram Eldar, Oct 06 2020 *)
PROG
(PARI) list(lim)=my(v=List([1])); forfactored(n=15, lim\1, if(n[2][1, 1]>2 && vecmax(n[2][, 2])==1 && #(n[2][, 2])%2==0, listput(v, n[1]))); Vec(v) \\ Charles R Greathouse IV, Nov 05 2017
(Magma) [k:k in [1..303 by 2]| IsSquarefree(k) and IsEven(#PrimeDivisors(k))]; // Marius A. Burtea, Jan 21 2020
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
James A. Sellers, Jul 07 2000
STATUS
approved