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A143221 a(0)=1. For n >=1, a(n) = 0 if the binary representation of n occurs at least once in the concatenation of (a(0),a(1),...,a(n-1)). a(n) = 1 otherwise. +0
3
1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1 (list; graph; listen)
OFFSET

0,1

LINKS

Leroy Quet, Home Page (listed in lieu of email address)

EXAMPLE

The binary representation of 21 is 10101. This occurs in the concatenation of terms a(0) through a(20) like so: 10010111(10101)00010010. So a(21) = 0.

MATHEMATICA

f[l_List]:=Append[l, Boole[StringPosition[ToString[FromDigits[l]], ToString[FromDigits[IntegerDigits[Length[l], 2]]]]=={}]]; Nest[f, {1}, 125] [From Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 09 2008]

CROSSREFS

Cf. A143220, A143222.

Sequence in context: A143580 A011749 A104105 this_sequence A126999 A120527 A071004

Adjacent sequences: A143218 A143219 A143220 this_sequence A143222 A143223 A143224

KEYWORD

base,nonn

AUTHOR

Leroy Quet, Jul 30 2008

EXTENSIONS

Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 09 2008

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Last modified November 23 10:40 EST 2009. Contains 167421 sequences.


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