This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A099862 #25 Nov 15 2024 22:38:25 %S A099862 6,9,12,15,18,21,24,26,28,32,34,36,39,42,45,48,50,52,55,57,60,63,65, %T A099862 68,70,74,76,78,81,84,86,88,91,93,95,98,100,104,106,110,112,115,117, %U A099862 119,121,123,125,128,130,133,135,138,141,143,145,147,150,153,155,158,160 %N A099862 a(n) = (2*k)-th composite number; a bisection of A002808. %e A099862 a(1) = 6 is the second composite number. %p A099862 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 %t A099862 Partition[Select[Range[200], CompositeQ], 2][[All, 2]] (* _Jean-François Alcover_, Mar 22 2023 *) %Y A099862 Cf. A002808, A099861. %Y A099862 Complement of A377898. %K A099862 nonn,easy %O A099862 1,1 %A A099862 _N. J. A. Sloane_, Nov 19 2004 %E A099862 More terms from _Emeric Deutsch_, Dec 09 2004