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%I #7 Apr 06 2018 11:41:25
%S 1,3,11,22,39,59,85,114,149,187,231,278,331,387,449,514,585,659,739,
%T 822,911,1003,1101,1202,1309,1419,1535,1654,1779,1907,2041,2178,2321,
%U 2467,2619,2774,2935,3099,3269,3442,3621,3803,3991,4182,4379,4579,4785,4994,5209
%N a(n) = 9*n^2/4 -4*n +19/8 -3*(-1)^n/8.
%F a(n)= 2*a(n-1) -2*a(n-3) +a(n-4).
%F G.f.: -x*(1+x+5*x^2+2*x^3)/((1+x)*(x-1)^3).
%t M := {{0, 1}, {-1, 2} }
%t v[1] = {1, 3}
%t w[n_] = If[Mod[n, 2] == 1, {0, 3}, {0, 6}]
%t v[n_] := v[n] = M.v[n - 1] + w[n]
%t Table[v[n][[1]], {n, 1, 30}]
%Y Cf. A003215, A005448.
%K nonn,easy
%O 1,2
%A _Roger L. Bagula_, Sep 07 2006
%E Definition replaced by polynomial - The Assoc. Editors of the OEIS, Oct 14 2009
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