cp's OEIS Frontend

A061921 A list of equal temperaments (equal divisions of the octave) whose nearest scale steps are closer and closer approximations to the 11 pairs of target ratios needed to express the 22 steps of the theoretical Hindu scale known as the 22 Srutis: 45/32 and 64/45, 27/20 and 40/27, 4/3 and 3/2, 81/64 and 128/81, 5/4 and 8/5, 6/5 and 5/3, 32/27 and 27/16, 9/8 and 16/9, 10/9 and 9/5, 16/15 and 15/8, 256/243 and 243/128.

%I A061921 #1 May 16 2003 03:00:00
%S A061921 1,2,3,4,5,6,7,8,9,10,11,12,28,29,30,32,34,37,39,40,41,53,118,171,323,
%T A061921 335,376,388,441,494,506,559,612,1171,1783,2513,3072,3125,3684,4296,
%U A061921 12276,16572,20868,40565,44861,48545,52841,57137,61433,69413,73709
%N A061921 A list of equal temperaments (equal divisions of the octave) whose nearest scale steps are closer and closer approximations to the 11 pairs of target ratios needed to express the 22 steps of the theoretical Hindu scale known as the 22 Srutis: 45/32 and 64/45, 27/20 and 40/27, 4/3 and 3/2, 81/64 and 128/81, 5/4 and 8/5, 6/5 and 5/3, 32/27 and 27/16, 9/8 and 16/9, 10/9 and 9/5, 16/15 and 15/8, 256/243 and 243/128.
%C A061921 The sequence was found by a computer search of all the equal divisions of the octave from 1 to 73709. The numerical value of each term represents a musical scale based on an equal division of the octave. The term 32, for example, signifies the scale which is formed by dividing the octave into 32 equal parts.
%F A061921 Recurrence rule: The next term equals the current term plus one or more previous terms: a(n+1) = a(n) + a(n-x)... + a(n-y)... + a(n-z), etc.
%e A061921 118 = 53 + [34 + 31]; Again, 229719 = 78005 + [73709 + 69413 + 4296 + 3684 + 612].
%Y A061921 A054540, A060525, A060526, A060527, A060528, A060529, A060233, A061416, A061918, A061919, A061920.
%K A061921 nonn
%O A061921 1,2
%A A061921 Mark William Rankin (MarkRankin95511(AT)Yahoo.com), May 15 2001