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 A260775 #18 May 08 2021 11:30:41 %S A260775 1,4,28,264,2860,33592,416024,5348880,70715340,955277400,13128240840, %T A260775 182965127280,2579808294648,36734706144304,527495903500720, %U A260775 7629973004184608,111068129754096396,1625888084299461528,23919596771720906984,353467725574013402800 %N A260775 Certain directed lattice paths. %C A260775 See Dziemianczuk (2014) for precise definition. %H A260775 Lars Blomberg, <a href="/A260775/b260775.txt">Table of n, a(n) for n = 0..100</a> %H A260775 M. Dziemianczuk, <a href="http://arxiv.org/abs/1410.5747">On Directed Lattice Paths With Additional Vertical Steps</a>, arXiv preprint arXiv:1410.5747 [math.CO], 2014. %H A260775 Maciej Dziemiańczuk, <a href="https://doi.org/10.1016/j.disc.2015.11.001">On directed lattice paths with vertical steps</a>, Discrete Math., 339 (2016), 1116-1139. %H A260775 Alex Hall, <a href="https://alexmojaki.github.io/oeis-explorer/">OEIS explorer</a> %F A260775 See Dziemianczuk (2014) Equation (36b) with N=2. %F A260775 a(n) = 2 * A000108(2*n) for n > 0. [Agrees with the reference, found using OEIS explorer.] - _Andrey Zabolotskiy_, May 08 2021 %Y A260775 Cf. A000108, A260769, A260770, A260771, A260772, A260773, A260774, A260776. %K A260775 nonn,easy %O A260775 0,2 %A A260775 _N. J. A. Sloane_, Jul 30 2015 %E A260775 More terms from _Lars Blomberg_, Aug 01 2015