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 A205493 #34 Oct 24 2024 23:52:21
%S A205493 1,14,109,623,2951,12331,47191,169416,579889,1914226,6144668,19298724,
%T A205493 59579803,181448918,546629054,1632497850,4841448042,14277423006,
%U A205493 41912838982,122587133760,357476552161,1039922075888,3019280091491,8752184436454,25337900299765
%N A205493 Third row or column of table A205497.
%C A205493 See A205497 regarding association of this sequence with generating functions for the rows of the tabular form of A050446.
%H A205493 L. E. Jeffery, <a href="/wiki/User:L._Edson_Jeffery/Unit-Primitive_Matrices">Unit-primitive matrices</a>
%F A205493 Conjecture 1. a(n) = M_{n,3} = M_{3,n}, where M = A205497.
%F A205493 Conjecture 2. Let w=2*cos(Pi/9). Then lim_{n->oo} a(n+1)/a(n) = w^3-2*w = spectral radius of the 4 X 4 unit-primitive matrix (see [Jeffery]) A_{9,3} = [0,0,0,1; 0,0,1,1; 0,1,1,1; 1,1,1,1].
%o A205493 (Python) # See program in A205497.
%Y A205493 Cf. A205497, A050446, A050447.
%K A205493 nonn
%O A205493 0,2
%A A205493 _L. Edson Jeffery_, Jan 28 2012
%E A205493 a(24) and changed title from _Hugo Pfoertner_, Jan 05 2020