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 A188148 Number of 3-step self-avoiding walks on an n X n square summed over all starting positions. 1
 0, 8, 44, 104, 188, 296, 428, 584, 764, 968, 1196, 1448, 1724, 2024, 2348, 2696, 3068, 3464, 3884, 4328, 4796, 5288, 5804, 6344, 6908, 7496, 8108, 8744, 9404, 10088, 10796, 11528, 12284, 13064, 13868, 14696, 15548, 16424, 17324, 18248, 19196, 20168, 21164 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Row 3 of A188147. LINKS R. H. Hardin, Table of n, a(n) for n = 1..50 FORMULA Empirical: a(n) = 12*n^2 - 24*n + 8 for n>1. Conjectures from Colin Barker, Apr 26 2018: (Start) G.f.: 4*x^2*(2 + 5*x - x^2) / (1 - x)^3. a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>4. (End) EXAMPLE Some solutions for 3 X 3: ..0..3..0....0..0..0....0..1..0....1..0..0....0..1..0....0..0..0....0..3..0 ..0..2..0....0..3..0....0..2..3....2..0..0....0..2..0....3..2..1....0..2..1 ..0..1..0....0..2..1....0..0..0....3..0..0....0..3..0....0..0..0....0..0..0 CROSSREFS Cf. A188147. Sequence in context: A046377 A075816 A290787 * A316466 A100583 A261996 Adjacent sequences:  A188145 A188146 A188147 * A188149 A188150 A188151 KEYWORD nonn AUTHOR R. H. Hardin, Mar 22 2011 STATUS approved

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Last modified April 3 04:21 EDT 2020. Contains 333195 sequences. (Running on oeis4.)