id:A112865 - OEIS Search Results

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The n-th term t(n)=(-1)^S(n). S(n)=Sum[ b(k)*a(k), k=0,L-1] where n=Sum[a(k)*2^k, k=0,L-1] (Binary expansion of n) and b(k)=1 only if mod(k,2)=0, b(k)=0 otherwise. Closely related to the Thue-Morse sequence where all b(k) are 1. Also appears as the column at the ``one-third'' position of the Walsh-Hadamard matrix.

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1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1 (list; graph; listen)

	OFFSET	`0,1`
	FORMULA	`Recurrence: Seems to satisfy A_{k+1}= A_{k} (-t(k) A_{k}) where A_{0}={1, -1, 1, -1} and t(k) is the n-th element of the sequence.`
	CROSSREFS	`Sequence in context: A008836 A064179 A106400 this_sequence A121241 A122188 A130151` `Adjacent sequences: A112862 A112863 A112864 this_sequence A112866 A112867 A112868`
	KEYWORD	`easy,sign,uned`
	AUTHOR	`Arul Lakshminarayan (arul(AT)physics.iitm.ac.in), Sep 27 2005`

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Last modified July 26 23:19 EDT 2008. Contains 142293 sequences.

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