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 A290439 #7 Aug 28 2017 01:02:37 %S A290439 0,2,4,11,22,43,85,171,366,774,1586,3136,6123,12088,24283,49040,99031, %T A290439 200444,405931 %N A290439 a(n) = A289677(3*n+1). %C A290439 No formulas or recurrences are known for the important sequences A289670 and A289671. The essence of these two sequences is captured in the six entries A290436-A290441. Any numerical properties of these would be most welcome. %Y A290439 Cf. A284116, A284119, A284121, A289670-A289677, A290436-A290441. %K A290439 nonn,more %O A290439 0,2 %A A290439 _N. J. A. Sloane_, Aug 02 2017