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 A240135 #14 Oct 08 2018 20:24:37
%S A240135 1,3,8,18,40,96,224,480,1024,2304,5120,10752,22528,49152,102400,
%T A240135 212992,442368,917504,1966080,4194304,8650752,17825792,36700160,
%U A240135 75497472,159383552,327155712,671088640,1409286144,2952790016,6039797760,12348030976,25769803776
%N A240135 a(n) = composite(n)*2^(n - 3).
%e A240135 a(1)=1 because composite(1) * 2^(1-3) = 4 * 2^(-2) = 1;
%e A240135 a(2)=3 because composite(2) * 2^(2-3) = 6 * 2^(-1) = 3;
%e A240135 a(3)=8 because composite(3) * 2^(3-3) = 8 * 2^0 = 8.
%t A240135 #[[1]]*2^(#[[2]]-3)&/@Module[{cs=Select[Range[50],CompositeQ]},Thread[ {cs,Range[Length[cs]]}]] (* _Harvey P. Dale_, Oct 08 2018 *)
%Y A240135 Cf. A002808.
%K A240135 nonn,less
%O A240135 1,2
%A A240135 _Gerasimov Sergey_, Apr 02 2014