%I #15 Jul 16 2021 10:05:17
%S 0,0,2,5,13,33,75,166,358,754,1564,3203,6491,13043,26021,51596,101772,
%T 199828,390790,761537,1479337,2865589,5536719,10673010,20530866,
%U 39417766,75545728,144551167,276172727,526908583,1003986313,1910718488,3632257048,6897610216,13085528650,24801630845,46966595909,88866759433
%N Partial sums of A337281.
%D R. Schumacher, Explicit formulas for sums involving the squares of the first n Tribonacci numbers, Fib. Q., 58:3 (2020), 194-202.
%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (3,-1,-1,-3,1,1,1).
%F From _Colin Barker_, Sep 13 2020: (Start)
%F G.f.: x^2*(2 - x + x^3) / ((1 - x)*(1 - x - x^2 - x^3)^2).
%F a(n) = 3*a(n-1) - a(n-2) - a(n-3) - 3*a(n-4) + a(n-5) + a(n-6) + a(n-7) for n>6.
%F (End)
%Y Cf. A000073, A337281.
%K nonn
%O 0,3
%A _N. J. A. Sloane_, Sep 12 2020