

A133270


Groups of 4 numbers describing a sequence of Minor 7th chords by assigning numbers 1 to 12 to an octave.


4



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

1,2


COMMENTS

A sequence of blocks of 4 numbers by reading the partial sequence from the left as in A133269, but here the interval assignments are for a minor 7th at the 12 base tones, explicitly: 1> {1, 4, 8, 11}, 2> {2, 5, 9, 12}, 3> {3, 6, 10, 1}, 4> {4, 7, 11, 2}, 5> {5, 8, 12, 3}, 6> {6, 9, 1, 4}, 7> {7, 10, 2, 5}, 8> {8, 11, 3, 6}, 9> {9, 12, 4, 7}, 10> {10, 3, 5, 8}, 11> {11, 4, 6, 9}, 12> {12, 5, 7, 10}.


LINKS

Table of n, a(n) for n=1..94.
Wikipedia, Minor seventh chord


EXAMPLE

Comments from N. J. A. Sloane, Aug 27 2017: (Start)
Define 12 4note musical chords c(1), ..., c(12) by
1> {1, 4, 8, 11}, 2> {2, 5, 9, 12}, 3> {3, 6, 10, 1}, 4> {4, 7, 11, 2}, 5> {5, 8, 12, 3}, 6> {6, 9, 1, 4}, 7> {7, 10, 2, 5}, 8> {8, 11, 3, 6}, 9> {9, 12, 4, 7}, 10> {10, 3, 5, 8}, 11> {11, 4, 6, 9}, 12> {12, 5, 7, 10}.
The sequence is a 4column table starting with c(1) = {1, 4, 8, 11} = {a(1), a(2), a(3), a(4)} and then continuing by successively appending c(a(2)), c(a(3)), c(a(4)), c(a(5)), ...
The array begins:
1, 4, 8, 11,
4, 7, 11, 2,
8, 11, 3, 6,
11, 4, 6, 9,
4, 7, 11, 2,
7, 10, 2, 5,
11, 4, 6, 9,
2, 5, 9, 12,
8, 11, 3, 6,
11, 4, 6, 9,
3, 6, 10, 1,
...
(End)


MATHEMATICA

Clear[s, p] s[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]}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n  1]]; p[4]


CROSSREFS

Cf. A133269.
Sequence in context: A316505 A293597 A131803 * A131517 A076689 A161867
Adjacent sequences: A133267 A133268 A133269 * A133271 A133272 A133273


KEYWORD

nonn,easy,tabf


AUTHOR

Roger L. Bagula, Oct 16 2007


EXTENSIONS

Comments inserted for clarification  The Assoc. Eds. of the OEIS, Aug 29 2010
Edited by N. J. A. Sloane, Aug 27 2017


STATUS

approved



