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A134751 Hankel transform of expansion of (1/(1-x^2))c(x/(1-x^2)), where c(x) is the g.f. of A000108. 5

%I

%S 1,2,8,32,256,4096,65536,2097152,134217728,8589934592,1099511627776,

%T 281474976710656,72057594037927936,36893488147419103232,

%U 37778931862957161709568,38685626227668133590597632

%N Hankel transform of expansion of (1/(1-x^2))c(x/(1-x^2)), where c(x) is the g.f. of A000108.

%C Hankel transform of A105864.

%C The sequence 1,1,2,8,... with general term 2^floor(n^2/3) is the Hankel transform of A109033. [From _Paul Barry_, Dec 14 2008]

%C a(n)=4*e(n-1)*e(n-3)/e(n-4). Somos-4 sequence associated to e.g. y^2=1-8x+16x^2-8x^3. [From _Paul Barry_, Nov 27 2009]

%F a(n)=2^floor((n+1)^2/3); a(n)=Product{k=1..n, (5/3-2*cos(2*pi*k/3)/3)^(n-k+1)}; a(n)=Product{k=1..n, A130196(k)^(n-k+1)};

%K easy,nonn

%O 0,2

%A _Paul Barry_, Nov 08 2007

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Last modified September 21 06:18 EDT 2021. Contains 347596 sequences. (Running on oeis4.)