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 A039504 #9 Dec 19 2015 12:57:19
%S A039504 5,7,9,13,19,27,35,47,51,63,75,81,89,93,107,119,121,125,133,139,143,
%T A039504 149,159,161,167,177,181,187,191,199,203,215,223,237,241,251,255,265,
%U A039504 271,281,285,287,297,299,317,323,333,335,341,353,355,357,361,371,375
%N A039504 Odd numbers from A039501.
%t A039504 colln[n_]:= NestWhile[If[EvenQ[#], #/2, 3#-1] &, n, FreeQ[{1, 5, 17}, #] &]; Select[Range[1, 375, 2], colln[#] == 5 &] (* _Jayanta Basu_, Jun 06 2013 *)
%Y A039504 Cf. A037084, A039500-A039505.
%K A039504 nonn,easy
%O A039504 1,1
%A A039504 _Christian G. Bower_, Feb 15 1999