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 A292044 Wiener index of the n-halved cube graph. 0
 0, 1, 6, 32, 160, 768, 3584, 16384, 73728, 327680, 1441792, 6291456, 27262976, 117440512, 503316480, 2147483648, 9126805504, 38654705664, 163208757248, 687194767360, 2886218022912, 12094627905536, 50577534877696, 211106232532992, 879609302220800, 3659174697238528 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS a(n) is the sum of the first 2^(n-1) entries of A116640. - Joe Slater, Apr 11 2018 LINKS Eric Weisstein's World of Mathematics, Halved Cube Graph Eric Weisstein's World of Mathematics, Wiener Index Index entries for linear recurrences with constant coefficients, signature (8, -16). FORMULA a(n) = 2^(2*n-5)*n for n > 1. a(n) = 8*a(n-1) - 16*a(n-2) for n > 3. G.f.: ((1 - 2 x) x^2)/(1 - 4 x)^2. a(n) = 4*a(n-1) + 2^(2*n-5) for n > 2. - Joe Slater, Apr 11 2018 MATHEMATICA Table[If[n == 1, 0, 2^(2 n - 5) n], {n, 40}] Join[{0}, LinearRecurrence[{8, -16}, {1, 6}, 20]] CoefficientList[Series[((1 - 2 x) x)/(1 - 4 x)^2, {x, 0, 20}], x] PROG (PARI) a(n) = if(n<2, n-1, 2^(2*n-5)*n); \\ Altug Alkan, Apr 12 2018 CROSSREFS Sequence in context: A046725 A232331 A231992 * A006668 A232494 A037530 Adjacent sequences:  A292041 A292042 A292043 * A292045 A292046 A292047 KEYWORD nonn,easy AUTHOR Eric W. Weisstein, Sep 08 2017 STATUS approved

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Last modified December 1 20:10 EST 2021. Contains 349430 sequences. (Running on oeis4.)