OFFSET
0,2
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 342-349.
LINKS
Steven R. Finch, Hard Square Entropy Constant [Broken link]
Steven R. Finch, Hard Square Entropy Constant [From the Wayback machine]
Eric Weisstein's World of Mathematics, 01-Matrix.
MATHEMATICA
t[m_] := t[m] = Map[ArrayReshape[#, {m, m}] &, Tuples[{0, 1}, m^2]]; a[m_] := a[m] = Count[Table[AnyTrue[Flatten[{Table[Equal[1, t[m][[n, a, b]], t[m][[n, a, b + 1]], t[m][[n, a, b + 2]]], {a, 1, m}, {b, 1, m - 2}], Table[Equal[1, t[m][[n, a, b]], t[m][[n, a + 1, b]], t[m][[n, a + 2, b]]], {a, 1, m - 2}, {b, 1, m}]}], TrueQ], {n, 1, 2^(m^2)}], False]; (* Robert P. P. McKone, Jan 04 2022 *)
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
EXTENSIONS
More terms from R. H. Hardin, Feb 02 2002
a(0)=1 prepended and a(13)-a(16) from Peter J. Taylor, Sep 26 2024
STATUS
approved