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 A245827 Szeged index of the grid graph P_3 X P_n. 3
 4, 59, 216, 526, 1040, 1809, 2884, 4316, 6156, 8455, 11264, 14634, 18616, 23261, 28620, 34744, 41684, 49491, 58216, 67910, 78624, 90409, 103316, 117396, 132700, 149279, 167184, 186466, 207176, 229365, 253084, 278384, 305316, 333931, 364280, 396414, 430384, 466241, 504036, 543820 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 S. Klavzar, A. Rajapakse, I. Gutman, The Szeged and the Wiener index of graphs, Appl. Math. Lett., 9, 1996, 45-49. Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1). FORMULA a(n) = (1/2)*n*(17*n^2 - 9). a(n) = A245826(n, 3). a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4). G.f.: x*(4*x^2+43*x+4) / (x-1)^4. - Colin Barker, Aug 07 2014 MAPLE a := proc (n) options operator, arrow: (1/2)*n*(17*n^2-9) end proc: seq(a(n), n = 1 .. 40); MATHEMATICA CoefficientList[Series[(4 x^2 + 43 x + 4)/(x - 1)^4, {x, 0, 40}], x] (* Vincenzo Librandi, Aug 07 2014 *) LinearRecurrence[{4, -6, 4, -1}, {4, 59, 216, 526}, 40] (* Harvey P. Dale, Oct 21 2017 *) PROG (PARI) Vec(x*(4*x^2+43*x+4)/(x-1)^4 + O(x^100)) \\ Colin Barker, Aug 07 2014 (Magma) [(1/2)*n*(17*n^2 - 9): n in [1..40]]; // Vincenzo Librandi, Aug 07 2014 CROSSREFS Cf. A245826, A063521, A245828. Sequence in context: A144992 A198511 A282040 * A200048 A037066 A113251 Adjacent sequences: A245824 A245825 A245826 * A245828 A245829 A245830 KEYWORD nonn,easy AUTHOR Emeric Deutsch, Aug 06 2014 STATUS approved

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Last modified September 15 22:11 EDT 2024. Contains 375959 sequences. (Running on oeis4.)