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A106581
Alternating two level four-symbol substitution: characteristic polynomial: x^2*(x^2-3).
0
2, 4, 3, 1, 2, 2, 2, 4, 3, 1, 4, 3, 1, 4, 3, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3
OFFSET
0,1
COMMENTS
A triangle shaped digraph with one central point. Triangular levels as: {2}, {4, 3, 1}, {2, 2, 2}, {4, 3, 1, 4, 3, 1, 4, 3, 1}, {2, 2, 2, 2, 2, 2, 2, 2, 2}, {4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3, 1, 4, 3,1, 4, 3,1}, {2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,2, 2, 2,2}
FORMULA
1->{2}, 2->{4, 3, 1}, 3->{2}, 4->{2}.
MATHEMATICA
s[1] = {2}; s[2] = {4, 3, 1}; s[3] = {2}; s[4] = {2};
t[a_] := Flatten[s /@ a];
p[0] = {2}; p[n_] := t[p[n - 1]];
Table[p[i], {i, 0, 7}]//Flatten
CROSSREFS
Sequence in context: A134893 A227862 A229802 * A317612 A070402 A125941
KEYWORD
nonn,uned
AUTHOR
Roger L. Bagula, May 09 2005
STATUS
approved