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%I #5 Oct 18 2020 06:59:11
%S 1,3,11,51,255,1325,7039,37951,206799,1135969,6279509,34889553,
%T 194664283,1089943229,6120967411,34463104999,194474062663,
%U 1099571123853,6227893795649,35329149864161,200691916063033,1141489886332555
%N Even bisection of A113281: a(n) = A113281(2*n).
%F G.f.: ( (1+x)/(1-x)/(1-6*x+x^2)*(1-x+(1-6*x+x^2)^(1/2))/2 )^(1/2).
%F a(n) ~ (1 + sqrt(2))^(2*n + 1/2) / (2*sqrt(Pi*n)). - _Vaclav Kotesovec_, Oct 18 2020
%o (PARI) {a(n)=local(x=X+X*O(X^n));polcoeff( ((1+x)/(1-x)/(1-6*x+x^2)*(1-x+(1-6*x+x^2)^(1/2))/2)^(1/2),n,X)}
%Y Cf. A113281, A113282, A113284.
%K nonn
%O 0,2
%A _Paul D. Hanna_, Oct 22 2005
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