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A083582
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a(n) = (8*2^n-5*(-1)^n)/3.
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6
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1, 7, 9, 23, 41, 87, 169, 343, 681, 1367, 2729, 5463, 10921, 21847, 43689, 87383, 174761, 349527, 699049, 1398103, 2796201, 5592407, 11184809, 22369623, 44739241, 89478487, 178956969, 357913943, 715827881, 1431655767, 2863311529
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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a(n) = (8*2^n-5(-1)^n)/3.
G.f.: (1+6*x)/((1-2*x)*(1+x)).
E.g.f.: (8*exp(2*x)-5*exp(-x))/3.
a(n) = 2^(n+2)th coefficient of - eta(z)^3 eta(z^5) eta(z^10)^2 /eta(z^2)^2. - Kok Seng Chua (chuaks(AT)ihpc.a-star.edu.sg), Aug 30 2005
a(n) = a(n-1)+2*a(n-2). a(n)+a(n+1) = 8*A000079 = a(n+2)-a(n). - Paul Curtz, Jul 27 2008
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MAPLE
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BB := n->if n=1 then 3; > elif n=2 then 1; > else 2*BB(n-2)+BB(n-1); > fi: > L:=[]: for k from 2 to 32 do L:=[op(L), BB(k)]: od: L; # Zerinvary Lajos, Mar 19 2007
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MATHEMATICA
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LinearRecurrence[{1, 2}, {1, 7}, 40] (* Harvey P. Dale, May 28 2017 *)
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PROG
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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