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 A228702 Wiener index of generalized Fibonacci cube graph Q_n(111). 0
 0, 1, 8, 36, 164, 694, 2792, 11008, 42484, 161395, 606000, 2252856, 8307224, 30424076, 110774704, 401307232, 1447463192, 5200692085, 18622103160, 66476800796, 236657676956, 840418968098, 2977799304536, 10529449821312, 37162248493740, 130933420076839 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Table of n, a(n) for n=0..25. S. Klavzar and Y. Rho, On the Wiener index of generalized Fibonacci cubes and Lucas cubes, preprint (2013). FORMULA There is an explicit formula for a(n) in terms of tribonacci numbers (A000073). Empirical g.f.: x*(x^2+1)*(x^2+4*x+1) / ((x^3-x^2-x-1)^2*(x^3+x^2+3*x-1)^2). - Colin Barker, Sep 08 2013 PROG (Magma) /* From Klavzar and Rho paper, Theorem 2.4: */ T:=[n le 3 select Floor(n/3) else Self(n-1)+Self(n-2)+Self(n-3): n in [1..40]]; /* being T=A000073 */ [((268+67*n)*T[n+4]^2-(118+4*n)*T[n+4]*T[n+5]-(50-14*n)*T[n+4]*T[n+6] -(66+7*n)*T[n+5]^2+(90+16*n)*T[n+5]*T[n+6]-(18+6*n)*T[n+6]^2)/484: n in [0..#T-6]]; // Bruno Berselli, Sep 06 2013 CROSSREFS Cf. A000073. Sequence in context: A055918 A074404 A221701 * A200667 A200468 A200250 Adjacent sequences: A228699 A228700 A228701 * A228703 A228704 A228705 KEYWORD nonn AUTHOR N. J. A. Sloane, Sep 06 2013 EXTENSIONS More terms from Bruno Berselli, Sep 06 2013 STATUS approved

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Last modified April 19 18:05 EDT 2024. Contains 371798 sequences. (Running on oeis4.)