A301285 - OEIS

%I #14 Mar 30 2018 08:14:27

%S 1,3,6,10,12,14,20,23,22,27,34,34,34,40,46,47,46,51,60,60,56,64,74,71,

%T 68,77,86,84,80,88,100,97,90,101,114,108,102,114,126,121,114,125,140,

%U 134,124,138,154,145,136,151,166,158,148,162,180,171,158,175,194

%N Coordination sequence for node of type V2 in "car" 2-D tiling (or net).

%H Rémy Sigrist, <a href="/A301285/b301285.txt">Table of n, a(n) for n = 0..1000</a>

%H Reticular Chemistry Structure Resource (RCSR), <a href="http://rcsr.net/layers/car">The car tiling (or net)</a>

%H Rémy Sigrist, <a href="/A301285/a301285.png">Illustration of first terms</a>

%H Rémy Sigrist, <a href="/A301285/a301285.gp.txt">PARI program for A301285</a>

%F Conjectures from _Colin Barker_, Mar 30 2018: (Start)

%F G.f.: (1 + 2*x + 5*x^2 + 7*x^3 + 7*x^4 + 7*x^5 + 5*x^6 + 2*x^7 + x^8) / ((1 - x)^2*(1 + x^2)^2*(1 + x + x^2)).

%F a(n) = a(n-1) - 2*a(n-2) + 3*a(n-3) - 2*a(n-4) + 3*a(n-5) - 2*a(n-6) + a(n-7) - a(n-8) for n>8.

%F (End)

%o (PARI) See Links section.

%Y Cf. A301283.

%K nonn

%O 0,2

%A _N. J. A. Sloane_, Mar 23 2018

%E More terms from _Rémy Sigrist_, Mar 28 2018