%I A122068
%S A122068 1,3,10,35,126,462,1715,6419,24157,91238,345401,1309574,4970070,
%T A122068 18874261,71705865,272491891,1035680954,3936821259,14965658694,
%U A122068 56893879910,216295686467,822315097387,3126323230541,11885921055638
%N A122068 Let M = {{2, 1, 0, 0, 0, 0}, {1, 2, 1, 0, 0, 0}, {0, 1, 2, 1, 0, 0}, 
               {0, 0, 1, 2, 1, 0}, {0, 0, 0, 1, 2, 1}, {0, 0, 0, 0, 1, 2}}; v[1] 
               = {1, 1, 1, 1, 1, 1}; v[n] = M.v[n - 1]; then a(n) =v[n][[1]]
%D A122068 Peter Steinbach, "Golden Fields: A Case for the Heptagon", Mathematics 
               Magazine, Vol. 70, No. 1, Feb. 1997.
%t A122068 M = {{2, 1, 0, 0, 0, 0}, {1, 2, 1, 0, 0, 0}, {0, 1, 2, 1, 0, 0}, {0, 
               0, 1, 2, 1, 0}, {0, 0, 0, 1, 2, 1}, {0, 0, 0, 0, 1, 2}}; v[1] = {1, 
               1, 1, 1, 1, 1}; v[n_] := v[n] = M.v[n - 1]; a = Table[v[n][[1]], 
               {n, 1, 50}]
%Y A122068 Cf. A087946, A081567.
%Y A122068 Sequence in context: A047037 A134391 A087946 this_sequence A099908 A167403 
               A001700
%Y A122068 Adjacent sequences: A122065 A122066 A122067 this_sequence A122069 A122070 
               A122071
%K A122068 nonn
%O A122068 1,2
%A A122068 Gary Adamson (rlbagulatftn(AT)yahoo.com), Oct 15 2006