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%I #28 Aug 28 2017 04:19:35
%S 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,
%T 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,
%U 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
%N Groups of 4 numbers describing a sequence of Minor 7th chords by assigning numbers 1 to 12 to an octave.
%C 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}.
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Minor_seventh_chord">Minor seventh chord</a>
%e Comments from _N. J. A. Sloane_, Aug 27 2017: (Start)
%e Define 12 4-note musical chords c(1), ..., c(12) by
%e 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}.
%e The sequence is a 4-column 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)), ...
%e The array begins:
%e 1, 4, 8, 11,
%e 4, 7, 11, 2,
%e 8, 11, 3, 6,
%e 11, 4, 6, 9,
%e 4, 7, 11, 2,
%e 7, 10, 2, 5,
%e 11, 4, 6, 9,
%e 2, 5, 9, 12,
%e 8, 11, 3, 6,
%e 11, 4, 6, 9,
%e 3, 6, 10, 1,
%e ...
%e (End)
%t 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]
%Y Cf. A133269.
%K nonn,easy,tabf
%O 1,2
%A _Roger L. Bagula_, Oct 16 2007
%E Comments inserted for clarification - The Assoc. Eds. of the OEIS, Aug 29 2010
%E Edited by _N. J. A. Sloane_, Aug 27 2017
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