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G.f. A(x) satisfies A(x) = 1 + x / (1 - x * A(x^2)).
3

%I #17 Nov 26 2023 08:37:50

%S 1,1,1,1,2,3,5,8,13,21,35,57,94,154,254,417,687,1129,1859,3057,5032,

%T 8277,13623,22412,36883,60684,99862,164312,270384,444899,732093,

%U 1204629,1982228,3261701,5367131,8831505,14532200,23912499,39347839,64746320,106539481,175309363,288469809

%N G.f. A(x) satisfies A(x) = 1 + x / (1 - x * A(x^2)).

%C What does this sequence count?

%H Seiichi Manyama, <a href="/A218032/b218032.txt">Table of n, a(n) for n = 0..1000</a>

%o (PARI)

%o N=66; R=O('x^N); x='x+R;

%o F = 1 + x;

%o for (k=1,N+1, F = 1 + x / (1 - x * subst(F,'x,'x^2) ) + R; );

%o Vec(F)

%Y Cf. A319436, A349365.

%K nonn

%O 0,5

%A _Joerg Arndt_, Oct 19 2012