%I #6 Sep 16 2018 12:49:48
%S 1,8,73,674,6229,57572,532117,4918166,45456841,420141248,3883214593,
%T 35891157194,331729069789,3066052597532,28338422486797,
%U 261921856685246,2420849609444881,22375043097652088,206804483710406713
%N Trinomial transform of the Pell numbers (A000129).
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (10,-7).
%F a(n) = Sum[ Trinomial[n, k] Pell[k], {k, 0, 2n} ] where Trinomial[n, k] = trinomial coefficients (A027907)
%F G.f.: (-2x+1)/(7x^2-10x+1).
%t CoefficientList[Series[(-2x+1)/(7x^2-10x+1),{x,0,20}],x] (* or *) LinearRecurrence[{10,-7},{1,8},20] (* _Harvey P. Dale_, Sep 16 2018 *)
%K easy,nonn
%O 0,2
%A _Emanuele Munarini_, May 21 2003