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 A129285 #14 Nov 29 2019 20:52:33 %S A129285 3,4,8,20,44,92,188,380,856,2148,5024,17616,58768,176320,755904, %T A129285 3305920,13885184,69634816,348174336,2385273856,14652403712, %U A129285 102566830080,849285738496,6035962949632,44017806979072,308166534991872,2380768960708608,23410894780694528 %N A129285 a(n) = A129151(n) / 27. %F A129285 a(n+1) = A129283(a(n)), a(0) = 3. %F A129285 a(n) = A129284(n+1). - _Eric M. Schmidt_, Oct 22 2013 %F A129285 Thus a(n) = A129150(n+1) / 4 = A090636(n+3) / 4. - _M. F. Hasler_, Nov 27 2019 %o A129285 (Haskell) a129285 n = a129151 n `div` 27 -- _Reinhard Zumkeller_, Nov 01 2013 [Moved here from A129284, first erroneous line deleted. - _M. F. Hasler_, Nov 27 2019] %Y A129285 Cf. A129284 (essentially the same), A129283 (n + n'), A129286, A051674, A129150, A090636 (trajectory of 15 under arithmetic derivative A003415). %K A129285 nonn %O A129285 0,1 %A A129285 _Reinhard Zumkeller_, Apr 07 2007