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A026491
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a(n) = least k > a(n-1) such that A001285(k-1) = A001285(n-1) for n >= 1.
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3
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1, 4, 5, 8, 10, 12, 13, 16, 17, 20, 21, 24, 26, 28, 29, 32, 34, 36, 37, 40, 42, 44, 45, 48, 49, 52, 53, 56, 58, 60, 61, 64, 65, 68, 69, 72, 74, 76, 77, 80, 81, 84, 85, 88, 90, 92, 93, 96, 98, 100, 101, 104, 106, 108, 109, 112, 113, 116, 117
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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LINKS
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FORMULA
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MAPLE
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N:= 200: # for terms <= N
S:= StringTools:-ThueMorse(N):
R:= 1: r:= 1:
for n from 1 do
j:= SearchText(S[n], S, r+1..-1);
if j = 0 then break fi;
R:= R, r+j;
r:= r+j;
if r >= N then break fi;
od:
# alternative
option remember ;
local f, k ;
if n = 0 then
1;
else
for k from procname(n-1)+1 do
return k;
end if;
end do:
end if;
end proc:
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MATHEMATICA
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a[n_] := a[n] = If[n==0, 1, For[k = a[n-1]+1, True, k++, If[ThueMorse[k-1]==ThueMorse[n-1], Return[k]]]];
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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