A131803 A binary Major Minor chord substitution: Chord progression start vector {4, 11, 9, 2, 5, 7} Cmajor, Gminor,Fminor,BbMajor,Dbminor, Ebminor.

4, 8, 11, 3, 8, 12, 3, 7, 11, 4, 6, 9, 3, 6, 10, 1, 8, 12, 3, 7, 12, 4, 7, 11, 3, 6, 10, 1, 7, 10, 2, 5, 11, 4, 6, 9, 4, 8, 11, 3, 6, 10, 1, 5, 9, 12, 4, 7, 3, 6, 10, 1, 6, 10, 1, 5, 10, 2, 5, 9, 1, 4, 8, 11, 11, 4, 6, 9, 4, 8, 11, 3, 6, 10, 1, 5, 9, 12, 4, 7, 4, 8, 11, 3, 8, 12, 3, 7, 11, 4, 6, 9, 3, 6

Offset

1,1

Comments

This substitution sequence is very like a Jazz chord progression in major (even) and minor (odd) chords. I call it a melt down.

Links

Table of n, a(n) for n=1..94.

Formula

Start vector->{4, 11, 9, 2, 5, 7} 1->{1, 4, 8, 11}, 2->{2, 6, 9, 1}, 3->{3, 6, 10, 1}, 4->{4, 8, 11, 3}, 5->{5, 8, 12, 3}, 6->{6, 10, 1, 5}, 7->{7, 10, 2, 5}, 8->{8, 12, 3, 7}, 9->{9, 12, 4, 7}, 10->{10, 2, 5, 9}, 11->{11, 4, 6, 9}, 12->{12, 4, 7, 11}

Mathematica

s0[i_] := {i, If[i + 4 > 12, i - 8, i + 4], If[i + 7 > 12, i - 5, i + 7], If[i + 11 > 12, i - 1, i + 11]}; s1[i_] := {i, If[i + 3 > 12, i - 7, i + 3], If[i + 7 > 12, i - 5, i + 7], If[i + 10 > 12, i - 2, i + 10]}; s[i_] := If[Mod[i, 2] == 0, s0[i], s1[i]] t[a_] := Flatten[s /@ a]; p[0] = {4, 11, 9, 2, 5, 7}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]]; p[3]

Crossrefs

Cf. A133269, A133270.

Sequence in context: A109445 A316505 A293597 * A133270 A131517 A076689

Adjacent sequences: A131800 A131801 A131802 * A131804 A131805 A131806

Keyword

nonn,uned

Author

Roger L. Bagula, Oct 23 2007

Status

approved