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 A105315 Limited tetrahedron digraph 4-symbol substitution : characteristic polynomial: x^4-2*x-1. Each edge is taken only once. 0
 1, 1, 2, 3, 1, 2, 3, 2, 3, 3, 4, 4, 1, 2, 3, 2, 3, 3, 4, 4, 2, 3, 3, 4, 4, 3, 4, 4, 4, 1, 1, 1, 2, 3, 2, 3, 3, 4, 4, 2, 3, 3, 4, 4, 3, 4, 4, 4, 1, 1, 2, 3, 3, 4, 4, 3, 4, 4, 4, 1, 1, 3, 4, 4, 4, 1, 1, 4, 1, 1, 1, 2, 3, 2, 3, 1, 2, 3, 2, 3, 3, 4, 4, 2, 3, 3, 4, 4, 3, 4, 4, 4, 1, 1, 2, 3, 3, 4, 4, 3, 4, 4, 4, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS I've found two other matrix isomers of this sequence with the same characteristic polynomial: 1->{2,3} 2->{3} 3-{4} 4->{1,2} and: 1->{2,4} 2->{3} 3->{1,4} 4->{2} LINKS FORMULA 1->{2, 3}, 2->{3, 4}, 3->{4}, 4->{1} MATHEMATICA s[1] = {2, 3}; s[2] = {3, 4}; s[3] = {4}; s[4] = {1}; t[a_] := Join[a, Flatten[s /@ a]]; p[0] = {1}; p[1] = t[{1}]; p[n_] := t[p[n - 1]] aa = Flatten[Table[p[n], {n, 0, 4}]] CROSSREFS Sequence in context: A059832 A105316 A105933 * A328912 A130830 A131989 Adjacent sequences:  A105312 A105313 A105314 * A105316 A105317 A105318 KEYWORD nonn AUTHOR Roger L. Bagula, Apr 25 2005 STATUS approved

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Last modified November 27 15:31 EST 2021. Contains 349394 sequences. (Running on oeis4.)