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A215739 Even and odd composite squarefree numbers, interlaced. 1

%I #13 Nov 20 2022 13:20:22

%S 6,15,10,21,14,33,22,35,26,39,30,51,34,55,38,57,42,65,46,69,58,77,62,

%T 85,66,87,70,91,74,93,78,95,82,105,86,111,94,115,102,119,106,123,110,

%U 129,114,133,118,141,122,143,130,145,134,155,138,159,142,161,146,165

%N Even and odd composite squarefree numbers, interlaced.

%H Harvey P. Dale, <a href="/A215739/b215739.txt">Table of n, a(n) for n = 1..1000</a>

%F For k=1,2,.., a(2k-1)=A039956(k+1), a(2k)=A024556(k); A039956 Even squarefree numbers, A024556 Odd squarefree composite numbers.

%t Module[{nn=200,csfn,od,ev,len},csfn=Select[Range[nn],CompositeQ[ #] && SquareFreeQ[ #]&];od=Select[csfn,OddQ];ev=Select[csfn,EvenQ];len=Min[ Length[ od],Length[ev]];Riffle[Take[ev,len],Take[od,len]]] (* _Harvey P. Dale_, Nov 20 2022 *)

%Y Cf. A120944.

%K nonn

%O 1,1

%A _Zak Seidov_, Aug 22 2012

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Last modified September 4 12:50 EDT 2024. Contains 375683 sequences. (Running on oeis4.)