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 A249680 #7 Nov 04 2014 14:16:44 %S A249680 1,5,9,13,19,23,29,27,35,41,47,49,53,55,59,63,57,69,73,79,89,91,97,95, %T A249680 101,103,107,109,113,117,121,127,137,139,149,151,145,155,157,161,163, %U A249680 167,169,173,179,181,191,193,199,209,211,221,215,223,227,229,233,235 %N A249680 A084937(3n+1). %H A249680 Reinhard Zumkeller, <a href="/A249680/b249680.txt">Table of n, a(n) for n = 0..10000</a> %o A249680 (Haskell) %o A249680 a249680 = a084937 . (+ 1) . (* 3) -- _Reinhard Zumkeller_, Nov 04 2014 %Y A249680 Cf. A084937, A249681-A249683. %K A249680 nonn %O A249680 0,2 %A A249680 _N. J. A. Sloane_, Nov 03 2014