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A215739
Even and odd composite squarefree numbers, interlaced.
1
6, 15, 10, 21, 14, 33, 22, 35, 26, 39, 30, 51, 34, 55, 38, 57, 42, 65, 46, 69, 58, 77, 62, 85, 66, 87, 70, 91, 74, 93, 78, 95, 82, 105, 86, 111, 94, 115, 102, 119, 106, 123, 110, 129, 114, 133, 118, 141, 122, 143, 130, 145, 134, 155, 138, 159, 142, 161, 146, 165
OFFSET
1,1
LINKS
FORMULA
For k=1,2,.., a(2k-1)=A039956(k+1), a(2k)=A024556(k); A039956 Even squarefree numbers, A024556 Odd squarefree composite numbers.
MATHEMATICA
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 *)
CROSSREFS
Cf. A120944.
Sequence in context: A202749 A123623 A240990 * A161397 A145257 A245200
KEYWORD
nonn
AUTHOR
Zak Seidov, Aug 22 2012
STATUS
approved