OFFSET
0,1
COMMENTS
Double silver dragon 4-symbol substitution; characteristic polynomial x^4-4x^3+4x^2-4.
The existence of the two polynomials silver: x^4-2*x^3+x^2-4 and double silver: x^4-4x^3+4x^2-4 suggests that a Kenyon-like polynomial of a general form: x^4-p*x^3+q*x^2-r might exist with substitutions associated to it.
MATHEMATICA
s[1] = {2, 1, 1, 2}; s[2] = {3}; s[3] = {4, 3, 3, 4}; s[4] = {1}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] aa = p[5]
CROSSREFS
KEYWORD
nonn
AUTHOR
Roger L. Bagula, May 06 2005
STATUS
approved