cp's OEIS Frontend

A152933 Number of sets (in the Hausdorff metric geometry) at each location between two sets defining a polygonal configuration consisting of k 6-gonal polygonal components chained with string components of length 2 as k varies.

%I A152933 #16 Jul 03 2023 10:52:47
%S A152933 18,1197,80361,5394960,362185569,24314987763,1632363850242,
%T A152933 109587212856081,7357034536009605,493907598828348264,
%U A152933 33158022432323420133,2226032671355124283287,149442611182684237761426,10032689243282040048565125,673535162800540841393716209
%N A152933 Number of sets (in the Hausdorff metric geometry) at each location between two sets defining a polygonal configuration consisting of k 6-gonal polygonal components chained with string components of length 2 as k varies.
%H A152933 S. Schlicker, L. Morales, and D. Schultheis, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL12/Schlicker/schlicker.html">Polygonal chain sequences in the space of compact sets</a>, J. Integer Seq. 12 (2009), no. 1, Article 09.1.7, 23 pp.
%H A152933 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (67, 9).
%F A152933 Conjectures from _Colin Barker_, Jul 09 2020: (Start)
%F A152933 G.f.: 9*x*(2 - x) / (1 - 67*x - 9*x^2).
%F A152933 a(n) = 67*a(n-1) + 9*a(n-2) for n>2.
%F A152933 (End)
%p A152933 with(combinat): a := proc(n) local aa, b, c, d, lambda, delta, R, S, F, L, m, l: m:=3: l:=2: F := n -> fibonacci(n): L := n -> fibonacci(n-1)+fibonacci(n+1): aa := (m, l) -> L(2*m)*F(l-2)+F(2*m+2)*F(l-1): b := (m, l) -> L(2*m)*F(l-1)+F(2*m+2)*F(l): c := (m, l) -> F(2*m+2)*F(l-2)+F(m+2)^2*F(l-1): d := (m, l) -> F(2*m+2)*F(l-1)+F(m+2)^2*F(l): lambda := (m,l) -> (d(m, l)+aa(m, l)+sqrt((d(m, l)-aa(m, l))^2+4*b(m, l)*c(m, l)))*(1/2): delta := (m,l) -> (d(m, l)+aa(m, l)-sqrt((d(m, l)-aa(m, l))^2+4*b(m, l)*c(m, l)))*(1/2): R := (m,l) -> ((lambda(m, l)-d(m, l))*L(2*m)+b(m, l)*F(2*m+2))/(2*lambda(m, l)-d(m, l)-aa(m, l)): S := (m,l) -> ((lambda(m, l)-aa(m, l))*L(2*m)-b(m, l)*F(2*m+2))/(2*lambda(m, l)-d(m, l)-aa(m, l)): simplify(R(m, l)*lambda(m, l)^(n-1)+S(m, l)*delta(m, l)^(n-1)); end proc;
%Y A152933 Cf. A152927, A152928, A152929, A152930, A152931, A152932, A152934, A152935.
%K A152933 nonn
%O A152933 1,1
%A A152933 _Steven Schlicker_, Dec 15 2008