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A099862
a(n) = (2*k)-th composite number; a bisection of A002808.
3
6, 9, 12, 15, 18, 21, 24, 26, 28, 32, 34, 36, 39, 42, 45, 48, 50, 52, 55, 57, 60, 63, 65, 68, 70, 74, 76, 78, 81, 84, 86, 88, 91, 93, 95, 98, 100, 104, 106, 110, 112, 115, 117, 119, 121, 123, 125, 128, 130, 133, 135, 138, 141, 143, 145, 147, 150, 153, 155, 158, 160
OFFSET
1,1
EXAMPLE
a(1) = 6 is the second composite number.
MAPLE
c:=proc(n) if isprime(n) then else n fi end: B:=[seq(c(n), n=2..250)]: seq(B[2*m], m=1..75); # Emeric Deutsch, Dec 09 2004
MATHEMATICA
Partition[Select[Range[200], CompositeQ], 2][[All, 2]] (* Jean-François Alcover, Mar 22 2023 *)
CROSSREFS
Complement of A377898.
Sequence in context: A214777 A239310 A130699 * A014407 A315952 A100352
KEYWORD
nonn,easy,changed
AUTHOR
N. J. A. Sloane, Nov 19 2004
EXTENSIONS
More terms from Emeric Deutsch, Dec 09 2004
STATUS
approved