A374646 Paradiddle version of Thue-Morse sequence.

1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1

Offset: 0

Author

Robert P. P. McKone, Jul 15 2024

Keywords

• nonn
• easy

Comments

A paradiddle is a basic drum pattern, either "left left right left" or "right right left right". We can take left, right to be either 0, 1 or 1, 0.

Limiting word of the morphism with maps 0 |--> 0100, 1 |--> 1011 and axiom 1011. - Joerg Arndt, Jul 15 2024

Examples

			k = 0: Sequence starts at its simplest form;
1.
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k = 1: The 1 of the initial sequence expands following the morphism rules, where 1 -> {1, 0, 1, 1} and 0 -> {0, 1, 0, 0}, resulting in;
1, 0, 1, 1.
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k = 2: Each element of the initial sequence expands following the morphism rules, where 1 -> {1, 0, 1, 1} and 0 -> {0, 1, 0, 0};
1, 0, 1, 1,
0, 1, 0, 0,
1, 0, 1, 1,
1, 0, 1, 1.
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k = 3: The expansion is applied recursively, giving:
1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1,
0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0,
1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1,
1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1.
		

Links

• Robert P. P. McKone, Table of n, a(n) for n = 0..16383
• Index entries for sequences that are fixed points of mappings

Crossrefs

Cf. A160381, A130198 (single paradiddle), A010059, A010060, A374724.

Programs

Mathematica

SubstitutionSystem[{1 -> {1, 0, 1, 1}, 0 -> {0, 1, 0, 0}}, {1}, {4}] // Flatten

PARI

first(n,v=[1])=if(n>4*#v, v=first((n+3)\4)); my(u=List()); for(i=1,#v-1, listput(u,v[i]); listput(u,1-v[i]); listput(u,v[i]); listput(u,v[i])); my(t=vector(n-#u,i,if(i==2,1-v[#v],v[#v]))); for(j=1,#t, listput(u,t[j])); Vec(u) \\ Charles R Greathouse IV, Jul 31 2024

Formula

a(n) = A160381(n)+1 mod 2. - Kevin Ryde, Dec 28 2024