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A133768 An example of a sequence composed of two twelve tone substitutions and two binary sequences: c(n)=bn1(n)*a(n)+bn2(n)*b(n) The resulting sequence is a substitution on 24 tones and zero: 25 tones total. 0
2, 9, 0, 12, 9, 0, 12, 0, 8, 12, 6, 6, 12, 0, 0, 11, 4, 0, 23, 0, 9, 10, 0, 8, 23, 4, 13, 11, 0, 0, 11, 0, 16, 0, 3, 7, 11, 4, 7, 9, 3, 7, 10, 0, 0, 20, 1, 10, 0, 8, 6, 0, 4, 8, 11, 5, 13, 9, 2, 0, 11, 3, 0, 10, 9, 9, 11, 0, 16, 0, 4, 5, 12, 4, 7, 11, 2, 0, 9, 15, 0, 11, 2, 0, 1, 5, 5, 12, 2, 13, 11 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Suppose that you have two known sequences of finite length on a limited alphabet: a[n], b[n] Such that a[n]<>b[n] ( doesn't equal) and you have two binary sequences bn1[n] and bn2[n] such that you can construct: c[n]=bn1[n]*a[n]+bn2[n]*b[n] Then there are four possibilities for the sums: c[n]=0 c[n]=a[n] c[n]=b[n] c[n]=a[n]+b[n] Since a[n]<>b[n], these are distinguishable, so that using these two sequences a simple code of two binary sequences can be coded on a single sequence with a limited alphabet. My 12 tone sequences would limit the total alphabet to 24 characters. By skipping any case where a[n]=b[n], the use of any general set of {a,b} sequences is possible. It doesn't matter if they repeat in one sequence of the other, just that they aren't the same. The information is in the binary sequence and this can be taken as a coding of any number of bits in pairs. It can work on lower substitutions as well, but maybe not as well since it is more likely in a level 3 substitution that a[n]=b[n] than in a 12th level substitution. Something like a Fibonacci sequence would involve too large of numbers, so substitutions are more natural. In this sequence I haven't worried about a(n)=b(n) and just constructed a general sequence of this type.

LINKS

Table of n, a(n) for n=1..91.

FORMULA

a(n)=A133270(n); b(n)=A133269(n); bn1(n)=Mod[A004001(n),2]; bn2[n]=Mod[A005229(n),2]; c(n)=bn1(n)*a(n)+bn2(n)*b(n)

MATHEMATICA

Clear[a, Conway, Mallows] (* sequence A004001*) Conway[1] = Conway[2] = 1; Conway[n_Integer?Positive] := Conway[n] = Conway[Conway[n - 1]] + Conway[n - Conway[n - 1]] (* sequence A005229*) Mallows[n_Integer?Positive] := Mallows[n] = Mallows[Mallows[n - 2]] + Mallows[n - Mallows[n - 2]] Mallows[0] = Mallows[1] = Mallows[2] = 1; (* minor A133270*) 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]]; P1 = p[4]; (*Major A133269*) Clear[s, p] s[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]}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]]; P2 = p[4]; aout = Table[Mod[Conway[n], 2]*P1[[n]] + Mod[Mallows[n], 2]*P2[[n]], { n, 1, Min[Length[P1], Length[P2]]}]

CROSSREFS

Cf. A133270, A133269, A004001, A005229.

Sequence in context: A188619 A020817 A245217 * A085333 A248853 A272003

Adjacent sequences:  A133765 A133766 A133767 * A133769 A133770 A133771

KEYWORD

nonn,uned

AUTHOR

Roger L. Bagula, Jan 02 2008

STATUS

approved

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Last modified March 5 16:55 EST 2021. Contains 341827 sequences. (Running on oeis4.)