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A048493
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a(n) = (n+1)*2^n - n.
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7
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1, 3, 10, 29, 76, 187, 442, 1017, 2296, 5111, 11254, 24565, 53236, 114675, 245746, 524273, 1114096, 2359279, 4980718, 10485741, 22020076, 46137323, 96468970, 201326569, 419430376, 872415207, 1811939302, 3758096357, 7784628196, 16106127331, 33285996514
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OFFSET
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0,2
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COMMENTS
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Old definition was: "a(n) = T(n,n), array T given by A048483".
Also the number of connected induced subgraphs in the n-sunlet graph. - Eric W. Weisstein, May 25 2017
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LINKS
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FORMULA
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a(n) = 5*a(n-1)-7*a(n-2)-a(n-3)+8*a(n-4)-4*a(n-5). - Colin Barker, Nov 26 2014
G.f.: -(4*x^3-5*x^2+3*x-1) / ((x-1)^2*(2*x-1)^2). - Colin Barker, Nov 26 2014
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MATHEMATICA
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LinearRecurrence[{6, -13, 12, -4}, {3, 10, 29, 76}, 20] (* Eric W. Weisstein, May 25 2017 *)
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PROG
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(PARI) Vec(-(4*x^3-5*x^2+3*x-1)/((x-1)^2*(2*x-1)^2) + O(x^100)) \\ Colin Barker, Nov 26 2014
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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