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
Wikipedia, Minor seventh chord
EXAMPLE
Comments from N. J. A. Sloane, Aug 27 2017: (Start)
Define 12 4-note 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 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)), ...
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
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