Eric Weisstein's World of Mathematics, <a href="httphttps://mathworld.wolfram.com/ElementaryCellularAutomaton.html">Elementary Cellular Automaton</a>
reviewed
approved
proposed
reviewed
editing
proposed
From Chai Wah Wu, Nov 01 2018: (Start)
a(n) = a(n-1) + 4*a(n-2) - 4*a(n-3) for n > 5 (conjectured).
G.f.: (16*x^5 - 20*x^4 + 6*x^3 + 1)/((x - 1)*(2*x - 1)*(2*x + 1)) (conjectured). (End)
approved
editing
proposed
approved
editing
proposed
Conjecture: For odd n > 3, a(n) = 2^(n-1) - 1, for even n > 3, a(n) = 3*2^(n-1) - 1. - David A. Corneth, Jul 23 2017
proposed
editing
editing
proposed