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%I #25 Feb 21 2020 21:01:12
%S 1,6,40,200,1056,4928,23808,107136,494080,2173952,9744384,42225664,
%T 185679872,795770880,3451518976,14668955648,62970789888,265876668416,
%U 1132226150400,4755349831680,20120910954496,84141991264256,354160151101440,1475667296256000,6184144161734656
%N Wiener index of the n-folded cube graph.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/FoldedCubeGraph.html">Folded Cube Graph</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/WienerIndex.html">Wiener Index</a>
%F G.f.: (1 + 4*x - sqrt(1 - 16*x^2))/(4*(1 - 4*x)^2 (1 + 4*x)).
%F D-finite with recurrence: (-n+1)*a(n) + 4*(2*n-3)*a(n-1) + 64*(-2*n+5)*a(n-3) + 256*(n-3)*a(n-4) = 0. - Adapted to offset by _R. J. Mathar_, Feb 21 2020
%F a(n) = 2^(n-3)*n*(2^(n-1) - binomial(n-1, floor((n-1)/2))). - _Andrew Howroyd_, Sep 08 2017
%t Table[2^(n - 3) n (2^(n - 1) - Binomial[n - 1, Floor[(n - 1)/2]]), {n, 2, 20}]
%t CoefficientList[Series[(1 + 4 x - Sqrt[1 - 16 x^2])/(4 x (1 - 4 x)^2 (1 + 4 x)), {x, 0, 20}], x]
%o (PARI) a(n) = 2^(n-3)*n*(2^(n-1) - binomial(n-1, floor((n-1)/2))); \\ _Andrew Howroyd_, Sep 08 2017
%Y Cf. A192826.
%K nonn
%O 2,2
%A _Eric W. Weisstein_, Sep 07 2017