id:A129760 - OEIS Search Results

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Bitwise AND of n-1 and n written in base 2.

+0
3

0, 0, 2, 0, 4, 4, 6, 0, 8, 8, 10, 8, 12, 12, 14, 0, 16, 16, 18, 16, 20, 20, 22, 16, 24, 24, 26, 24, 28, 28, 30, 0, 32, 32, 34, 32, 36, 36, 38, 32, 40, 40, 42, 40, 44, 44, 46, 32, 48, 48, 50, 48, 52, 52, 54, 48, 56, 56, 58, 56, 60, 60, 62, 0, 64, 64, 66, 64, 68, 68, 70, 64, 72, 72, 74 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`Also the number of Ducci sequences with period n.`
	REFERENCES	`R. Brown and J. L. Merzel, The number of Ducci sequences with a given period, Fib. Quart., 45 (2007), 115-121.`
	FORMULA	`Equals n - A006519(n). - N. J. A. Sloane (njas(AT)research.att.com), May 26 2008` `a(n) = n AND n-1`
	EXAMPLE	`a(6) = 6 AND 5 = binary 110 AND 101 = binary 100 = 4.`
	PROGRAM	`(C) int a(int n) { return n & (n-1); }`
	CROSSREFS	`Cf. A038712, A086799, A104594, A059991, A006519.` `Sequence in context: A134271 A094403 A166085 this_sequence A057377 A145811 A147980` `Adjacent sequences: A129757 A129758 A129759 this_sequence A129761 A129762 A129763`
	KEYWORD	`easy,nonn`
	AUTHOR	`Russ Cox (rsc(AT)swtch.com), May 15 2007`

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Last modified December 20 16:54 EST 2009. Contains 171081 sequences.

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