id:A157685 - OEIS Search Results

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a(n)=#{1<=k<=n : [K(k),K(k+1)]=[2,1]} where K=A000002

+0
4

0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 14, 14, 14, 15, 15, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 19, 19, 19, 20, 20, 20, 21, 21, 21, 22, 22, 22, 23, 23, 23, 24, 24, 24, 25, 25, 26, 26, 26 (list; graph; listen)

	OFFSET	`1,6`
	COMMENT	`Presumably a(n)=n/3+o(n)`
	PROGRAM	`(PARI) a(n)=sum(k=1, n, if(abs(A000002(k)-2)+abs(A000002(k+1)-1), 0, 1))`
	CROSSREFS	`Cf. A157684, A157686, A157687` `Sequence in context: A099741 A047743 A062299 this_sequence A127757 A079001 A032615` `Adjacent sequences: A157682 A157683 A157684 this_sequence A157686 A157687 A157688`
	KEYWORD	`nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), Mar 04 2009`

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Last modified November 24 23:16 EST 2009. Contains 167481 sequences.

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