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 A249776 Decimal expansion of the connective constant of the (3.12^2) lattice. 2
 1, 7, 1, 1, 0, 4, 1, 2, 9, 6, 8, 4, 4, 8, 4, 8, 4, 6, 4, 1, 1, 7, 0, 8, 7, 4, 6, 3, 1, 0, 4, 4, 5, 4, 0, 6, 7, 9, 9, 3, 2, 1, 9, 3, 2, 6, 9, 2, 4, 8, 1, 9, 5, 9, 7, 7, 0, 0, 8, 0, 7, 8, 5, 8, 3, 9, 4, 9, 2, 5, 0, 2 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS An algebraic integer of degree 12: largest real root of x^12 - 4x^8 - 8x^7 - 4x^6 + 2x^4 + 8x^3 + 12x^2 + 8x + 2. LINKS Charles R Greathouse IV, Illustration of the (3.12^2) lattice I. Jensen and A. J. Guttmann, Self-avoiding walks, neighbour-avoiding walks and trails on semiregular lattices, J. Phys. A: Math. Gen. 31 (1998), pp. 8137-8145. EXAMPLE 1.71104129684484846411708746310445406799321932692481959770080785839492... MATHEMATICA (* Illustration of the (3.12^2) lattice. *) hex312[frac_] := {Re[#], Im[#]} & /@   Flatten[Table[     With[{a = Exp[2 Pi I (n - 1/2)/6], b = Exp[2 Pi I ( n + 1/2)/6],       c = Exp[2 Pi I (n + 3/2)/6]}, {(1 - frac) b +        frac a, (1 - frac) b + frac c}], {n, 6}]] shiftPoly[shifts_, coords_] := Line[Append[#, #[[1]]]] & /@   Outer[#1 + #2 &, shifts*1.001, coords, 1, 1] tri = 1/5; (* Arbitrary, subject to 0 < tri < 1/2; determines size of triangles compared to hexagons. *) Graphics[{Gray,   shiftPoly[{{0, 0}, {Sqrt[3], 0}, {2 Sqrt[3], 0}, {3 Sqrt[3],      0}, {Sqrt[3]/2, 3/2}, {3 Sqrt[3]/2, 3/2}, {5 Sqrt[3]/2,      3/2}, {7 Sqrt[3]/2, 3/2}, {0, 3}, {Sqrt[3], 3}, {2 Sqrt[3],      3}, {3 Sqrt[3], 3}, {Sqrt[3]/2, 9/2}, {3 Sqrt[3]/2,      9/2}, {5 Sqrt[3]/2, 9/2}, {7 Sqrt[3]/2, 9/2}}, hex312[tri]]}] PROG (PARI) polrootsreal(x^12-4*x^8-8*x^7-4*x^6+2*x^4+8*x^3+12*x^2+8*x+2)[4] CROSSREFS Other connective constants: A179260 (hexagonal or honeycomb lattice). Sequence in context: A324007 A176442 A281115 * A053878 A070672 A319101 Adjacent sequences:  A249773 A249774 A249775 * A249777 A249778 A249779 KEYWORD nonn,cons AUTHOR Charles R Greathouse IV, Nov 05 2014 STATUS approved

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Last modified April 17 05:12 EDT 2021. Contains 343059 sequences. (Running on oeis4.)