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G.f. satisfies A(x) = 1 + x * A(x)^2 * (1 - A(x) + A(x)^2 - A(x)^3 + A(x)^4).
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%I #15 Apr 04 2024 09:47:11

%S 1,1,4,25,185,1501,12914,115723,1068505,10094770,97117624,948181724,

%T 9370734322,93562986440,942385174150,9563720899515,97696642766654,

%U 1003789888620166,10366477185870960,107548800153957745,1120374840689934195,11714707429579539268

%N G.f. satisfies A(x) = 1 + x * A(x)^2 * (1 - A(x) + A(x)^2 - A(x)^3 + A(x)^4).

%F G.f. A(x) satisfies:

%F (1) A(x)^2 = 1 + x * A(x)^2 * (1 + A(x)^5).

%F (2) A(x) = sqrt(B(x)) where B(x) is the g.f. of A366401.

%F a(n) = Sum_{k=0..n} binomial(n,k) * binomial(n+5*k/2+1/2,n)/(2*n+5*k+1).

%o (PARI) a(n) = sum(k=0, n, binomial(n, k)*binomial(n+5*k/2+1/2, n)/(2*n+5*k+1));

%Y Cf. A000108, A219537.

%Y Cf. A370472, A370476.

%Y Cf. A366401.

%K nonn

%O 0,3

%A _Seiichi Manyama_, Mar 31 2024