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 A278766 #5 Feb 16 2025 08:33:37
%S A278766 1,4,4,6,6,27,74,86,372,853,947,1475,3686,9084,19174,30737,1530833,
%T A278766 2401466,2521253,3649563,3802245,9320024,1092256819,2114664794,
%U A278766 2878948610,8842525055,13769551820,26996892389,215947176106,269439735691,13694290818678,18312336654245,19649485782723,63266709043539
%N A278766 Engel expansion of plastic constant (real root of x^3 - x - 1).
%H A278766 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/EngelExpansion.html">Engel Expansion</a>
%H A278766 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PlasticConstant.html">Plastic Constant</a>
%H A278766 <a href="/index/El#Engel">Index entries for sequences related to Engel expansions</a>
%e A278766 (1/2+sqrt(23/108))^(1/3) + (1/2-sqrt(23/108))^(1/3) = 1.324717957244... = 1/1 + 1/(1*4) + 1/(1*4*4) + 1/(1*4*4*6) + 1/(1*4*4*6*6) + 1/(1*4*4*6*6*27) + ...
%t A278766 EngelExp[A_, n_]:=Join[Array[1&, Floor[A]], First@Transpose@NestList[{Ceiling[1/Expand[ #[[1]]#[[2]]-1]], Expand[ #[[1]]#[[2]]-1]}&, {Ceiling[1/(A-Floor[A])], A-Floor[A]}, n-1]]; EngelExp[N[(1/2 + Sqrt[23/108])^(1/3) + (1/2 - Sqrt[23/108])^(1/3), 7! ], 40]
%Y A278766 Cf. A006784 (for definition of Engel expansion).
%Y A278766 Cf. A060006, A072117.
%K A278766 nonn,easy
%O A278766 1,2
%A A278766 _Ilya Gutkovskiy_, Nov 28 2016