A099862 - OEIS

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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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..61.

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