cp's OEIS Frontend

A121549 Number of ordered ways of writing n as a sum of two Fibonacci numbers (only one 1 is considered as a Fibonacci number).

%I A121549 #8 Oct 10 2022 12:34:50
%S A121549 0,1,2,3,2,3,2,2,2,3,2,0,2,2,2,3,0,2,0,0,2,2,2,2,0,3,0,0,2,0,0,0,0,2,
%T A121549 2,2,2,0,2,0,0,3,0,0,0,0,2,0,0,0,0,0,0,0,2,2,2,2,0,2,0,0,2,0,0,0,0,3,
%U A121549 0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,2,2,2,2,0,2,0,0,2,0,0,0,0,2,0,0,0
%N A121549 Number of ordered ways of writing n as a sum of two Fibonacci numbers (only one 1 is considered as a Fibonacci number).
%H A121549 Alois P. Heinz, <a href="/A121549/b121549.txt">Table of n, a(n) for n = 1..10000</a>
%F A121549 G.f.: (Sum_{i>=2} x^Fibonacci(i))^2.
%F A121549 a(n) = A121548(n,2).
%e A121549 a(6)=3 because we have 6=1+5=3+3=5+1.
%p A121549 with(combinat): g:=sum(z^fibonacci(i),i=2..30)^2: gser:=series(g,z=0,130): seq(coeff(gser,z,n),n=1..126);
%Y A121549 Cf. A000045, A121548, A121550, A357688, A357690, A357691.
%K A121549 nonn
%O A121549 1,3
%A A121549 _Emeric Deutsch_, Aug 07 2006