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A127284 a(n) = number of valleys (DU-steps) in the Dyck path encoded by A014486(n). 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; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..101.

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.

PROG

(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: A336931 A182662 A308778 * A120691 A111941 A153462

Adjacent sequences:  A127281 A127282 A127283 * A127285 A127286 A127287

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jan 16 2007

STATUS

approved

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Last modified April 20 08:38 EDT 2021. Contains 343125 sequences. (Running on oeis4.)