%I A121956
%S A121956 0,1,1,2,5,12,34,99,315,1042,3661,13354,51006,201561,826987,3498286,
%T A121956 15277665,68578942,316519868,1497639547,7263576113,36035247374,
%U A121956 182804409181,946808180148,5004540429504,26963932982089,148019711470333
%N A121956 3 X 3 matrix Marov with tribonacci-like structure with middle an n in 
               the matrix: Characteristic Polynomial x^3-x^2-n*x-1.
%F A121956 M = {{0, 1, 0}, {0, 0, 1}, {1, n, 1}}; v[0] = {0, 1, 1}; v[n_] := v[n] 
               = M.v[n - 1] a(n) = v[n][[1]]
%t A121956 M = {{0, 1, 0}, {0, 0, 1}, {1, n, 1}}; v[0] = {0, 1, 1}; v[n_] := v[n] 
               = M.v[n - 1] a = Table[v[n][[1]], {n, 0, 30}]
%Y A121956 Cf. A001053.
%Y A121956 Sequence in context: A076864 A032292 A151408 this_sequence A131467 A000103 
               A101292
%Y A121956 Adjacent sequences: A121953 A121954 A121955 this_sequence A121957 A121958 
               A121959
%K A121956 nonn,uned
%O A121956 1,4
%A A121956 Roger Bagula (rlbagulatftn(AT)yahoo.com), Sep 01 2006