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A253556
a(1) = 0; after which, a(2n) = a(n), a(2n+1) = 1 + a(A250470(n)).
7
0, 0, 1, 0, 2, 1, 3, 0, 1, 2, 4, 1, 5, 3, 2, 0, 6, 1, 7, 2, 1, 4, 8, 1, 2, 5, 3, 3, 9, 2, 10, 0, 2, 6, 3, 1, 11, 7, 4, 2, 12, 1, 13, 4, 1, 8, 14, 1, 3, 2, 2, 5, 15, 3, 2, 3, 3, 9, 16, 2, 17, 10, 5, 0, 4, 2, 18, 6, 2, 3, 19, 1, 20, 11, 6, 7, 4, 4, 21, 2, 4, 12, 22, 1, 3, 13, 3, 4, 23, 1, 3, 8, 1, 14, 5, 1, 24, 3, 7, 2, 25
OFFSET
1,5
COMMENTS
Consider the binary tree illustrated in A252753 and A252755: If we start from any n, computing successive iterations of A253554 until 1 is reached (i.e., we are traversing level by level towards the root of the tree, starting from that vertex of the tree where n is located at), a(n) gives the number of odd numbers > 1 encountered on the path (i.e., excluding the final 1 from the count but including the starting n if it was odd).
LINKS
FORMULA
a(1) = 0; after which, a(2n) = a(n), a(2n+1) = 1 + a(A250470(n)).
a(n) = A253555(n) - A253557(n).
a(n) = A253558(n) - 1.
a(n) = A080791(A252754(n)). [Number of nonleading 0-bits in A252754(n).]
Other identities. For all n >= 2:
a(n) = A000120(A252756(n)) - 1. [One less than the binary weight of A252756(n).]
PROG
(Scheme, with memoization-macro definec)
(definec (A253556 n) (cond ((= 1 n) 0) ((odd? n) (+ 1 (A253556 (A250470 n)))) (else (A253556 (/ n 2)))))
CROSSREFS
One less than A253558.
Powers of two, A000079, gives the positions of zeros.
Differs from A252735 for the first time at n=21, where a(21) = 1, while A252735(21) = 3.
Sequence in context: A307744 A119709 A328167 * A252735 A120251 A333429
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 12 2015
STATUS
approved