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%I #2 Mar 30 2012 17:34:28
%S 1,1,1,1,3,1,1,9,9,1,1,27,42,27,1,1,81,177,177,81,1,1,243,690,927,690,
%T 243,1,1,729,2553,4293,4293,2553,729,1,1,2187,9114,18387,22851,18387,
%U 9114,2187,1,1,6561,31713,74601,110304,110304,74601,31713,6561,1,1
%N A vector recursion sequence: k = -3; m = 3; l = -3; a(n)=k*{0,a(n-2),0}+m*{-(m-1)/m,a(n-1)}++m*{a(n-1),-(m-1)/m}+l*{0,0,a(n-4),0,0}.
%C The row sums are:
%C {1, 2, 5, 20, 98, 518, 2795, 15152, 82229, 446360, 2423084,...}
%F k = -3; m = 3; l = -3; a(n)=k*{0,a(n-2),0}+m*{-(m-1)/m,a(n-1)}++m*{a(n-1),-(m-1)/m}+l*{0,0,a(n-4),0,0}.
%e {1},
%e {1, 1},
%e {1, 3, 1},
%e {1, 9, 9, 1},
%e {1, 27, 42, 27, 1},
%e {1, 81, 177, 177, 81, 1},
%e {1, 243, 690, 927, 690, 243, 1},
%e {1, 729, 2553, 4293, 4293, 2553, 729, 1},
%e {1, 2187, 9114, 18387, 22851, 18387, 9114, 2187, 1},
%e {1, 6561, 31713, 74601, 110304, 110304, 74601, 31713, 6561, 1},
%e {1, 19683, 108258, 290871, 497484, 590490, 497484, 290871, 108258, 19683, 1}
%t Clear[a, k, m, l]; k = -3; m = 3; l = -3; a[0] = {1}; a[1] = {1, 1};
%t a[n_] := a[n] = k*Join[{0}, a[n - 2], {0}] + m*Join[{-(m - 1)/m}, a[n - 1]] + m*Join[a[n - 1], {-(m - 1)/m}] +
%t If[n >= 4, k*Join[{0, 0}, a[n - 4], {0, 0}], Table[0, {i, 0, n}]];
%t Table[a[n], {n, 0, 10}]; Flatten[%]
%K nonn,uned
%O 0,5
%A _Roger L. Bagula_, Dec 10 2008
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