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%I #8 Oct 10 2022 12:37:28
%S 0,0,1,3,6,7,9,9,10,9,12,12,9,9,10,12,12,12,12,6,9,6,12,13,9,12,12,9,
%T 12,6,12,6,0,9,6,9,15,9,13,9,6,12,9,12,9,0,12,6,6,12,0,6,0,0,9,6,9,12,
%U 9,15,9,6,13,6,9,6,0,12,9,9,12,0,9,0,0,12,6,6,6,0,12,0,0,6,0,0,0,0,9,6,9,12
%N Number of ordered ways of writing n as a sum of three Fibonacci numbers (only one 1 is considered as a Fibonacci number).
%H Alois P. Heinz, <a href="/A121550/b121550.txt">Table of n, a(n) for n = 1..10000</a>
%F G.f.: (Sum_{i>=2} x^Fibonacci(i))^3.
%F a(n) = A121548(n,3).
%e a(6)=7 because we have 6=1+2+3=1+3+2=2+1+3=2+3+1=3+1+2=3+2+1=2+2+2.
%p with(combinat): g:=sum(z^fibonacci(i),i=2..30)^3: gser:=series(g,z=0,130): seq(coeff(gser,z,n),n=1..126);
%Y Cf. A000045, A121548, A121549, A357688, A357690, A357691.
%K nonn
%O 1,4
%A _Emeric Deutsch_, Aug 07 2006
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