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 A121782 Series expansion for mean-squared radius of gyration of rectangles on square lattice. 1
 0, 8, 66, 288, 900, 2280, 4998, 9856, 17928, 30600, 49610, 77088, 115596, 168168, 238350, 330240, 448528, 598536, 786258, 1018400, 1302420, 1646568, 2059926, 2552448, 3135000, 3819400, 4618458, 5546016, 6616988, 7847400 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS I. Jensen, Table of n, a(n) for n = 1..55 (from link below) I. Jensen, Series expansions for self-avoiding polygons FORMULA All terms appear to be generated by n^2*(n-1)*(n^2+2)/3. - T. D. Noe, Feb 09 2007 Conjectures from Colin Barker, Apr 17 2017: (Start) G.f.: 2*x^2*(1 + x)^2*(4 + x) / (1 - x)^6. a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6. (End) CROSSREFS Sequence in context: A230736 A008893 A168302 * A212784 A121781 A121780 Adjacent sequences:  A121779 A121780 A121781 * A121783 A121784 A121785 KEYWORD nonn AUTHOR N. J. A. Sloane, Aug 30 2006 STATUS approved

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Last modified January 18 10:35 EST 2021. Contains 340254 sequences. (Running on oeis4.)