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%I #5 Oct 01 2022 00:36:50
%S 1,1,2,3,6,10,18,32,57,101,179,318,564,1002,1778,3157,5603,9947,17656,
%T 31342,55635,98759,175308,311191,552400,980571,1740625,3089803,
%U 5484750,9736045,17282576,30678512,54457808,96668726,171597851,304605465,540708924
%N Number of compositions (ordered partitions) of n into tribonacci numbers 1,2,4,7,13,24, ... (A000073).
%F G.f.: 1 / (1 - Sum_{k>=3} x^A000073(k)).
%t A000073[0] = A000073[1] = 0; A000073[2] = 1; A000073[n_] := A000073[n] = A000073[n - 1] + A000073[n - 2] + A000073[n - 3]; nmax = 36; CoefficientList[Series[1/(1 - Sum[x^A000073[k], {k, 3, 20}]), {x, 0, nmax}], x]
%Y Cf. A000073, A076739, A117546, A240844, A357453, A357455.
%K nonn
%O 0,3
%A _Ilya Gutkovskiy_, Sep 29 2022
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