A099862 a(n) = (2*k)-th composite number; a bisection of A002808.

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

Author

N. J. A. Sloane, Nov 19 2004

Keywords

• nonn
• easy

Examples

			a(1) = 6 is the second composite number.
		

Crossrefs

Cf. A002808, A099861.

Complement of A377898.

Programs

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 *)

Extensions

More terms from Emeric Deutsch, Dec 09 2004