id:A127284 - OEIS Search Results

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a(n) = number of valleys (DU-steps) in the Dyck path encoded by A014486(n).

+0
2

0, 0, 1, 0, 2, 1, 1, 1, 0, 3, 2, 2, 2, 1, 2, 1, 2, 2, 1, 1, 1, 1, 0, 4, 3, 3, 3, 2, 3, 2, 3, 3, 2, 2, 2, 2, 1, 3, 2, 2, 2, 1, 3, 2, 3, 3, 2, 2, 2, 2, 1, 2, 1, 2, 2, 1, 2, 2, 2, 1, 1, 1, 1, 1, 0, 5, 4, 4, 4, 3, 4, 3, 4, 4, 3, 3, 3, 3, 2, 4, 3, 3, 3, 2, 4, 3, 4, 4, 3, 3, 3, 3, 2, 3, 2, 3, 3, 2, 3, 3, 3, 2 (list; graph; listen)

	OFFSET	`0,5`
	FORMULA	`a(0)=0, a(n) = A057514(n)-1.`
	EXAMPLE	`A014486(2) = 10 (1010 in binary) which encodes Dyck path /\/\ with two peaks and one valley, thus a(2)=1.` `A014486(12) = 180 (10110100 in binary) which encodes Dyck path:` `..../\/\...` `./\/....\..` `which has two valleys, thus a(12) = 2.`
	PROGRAM	`(Scheme:) (define (A127284 n) (if (zero? n) 0 (- (A057514 n) 1)))`
	CROSSREFS	`a(A057163(n)) = A126306(n), a(n) = A126306(A057163(n)) for all n. Cf. A057516.` `Sequence in context: A117479 A118404 A089339 this_sequence A120691 A111941 A153462` `Adjacent sequences: A127281 A127282 A127283 this_sequence A127285 A127286 A127287`
	KEYWORD	`nonn`
	AUTHOR	`Antti Karttunen (His-Firstname.His-Surname(AT)gmail.com), Jan 16 2007`

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.

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