id:A163575 - OEIS Search Results

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The changepoint a(n) is the first predecessor from n in a binary tree with: a(n) mod 2 <> n mod 2

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0, 1, 0, 1, 2, 3, 0, 1, 4, 5, 2, 3, 6, 7, 0, 1, 8, 9, 4, 5, 10, 11, 2, 3, 12, 13, 6, 7, 14, 15, 0, 1, 16, 17, 8, 9, 18, 19, 4, 5, 20, 21, 10, 11, 22, 23, 2, 3, 24, 25, 12, 13, 26, 27, 6, 7, 28, 29, 14, 15, 30, 31, 0, 1, 32, 33, 16, 17, 34, 35, 8, 9, 36, 37, 18, 19, 38, 39, 4, 5, 40, 41, 20 (list; graph; listen)

	OFFSET	`1,5`
	COMMENT	`In a binary tree (node(row,col)=2^(row-1)+(col-1))` `__________1________` `_____2________3____` `____4_5______6_7___` `. . . . . . . . . .` `has any node 2 successors and one predecessor. a(n) ist the first` `predecessor from n (going back, step by step) with another last digit (in binary sight) as n.` `the subsequences from a(2^k) to a(2^(k+1) - 1) are permutations from the` `natural numbers from 0 to 2^k-1`
	LINKS	`Wikipedia, Calkin Wilf Tree` `Wikipedia, Stern Brocot Tree`
	EXAMPLE	`A(7) = A(b111) = b0 = 0` `A(17) = A(b10001) = b1000 = 8` `A(8) = A(b1000) = b1 = 1`
	PROGRAM	`(Other) FUNCTION CHANGEPOINT` `INPUT n` `IF EVEN(n)` `..WHILE EVEN(n)` `....n = n/2` `ELSE` `..WHILE NOT EVEN(n)` `....n = (n-1)/2` `OUTPUT n`
	CROSSREFS	`Sequence in context: A143325 A128888 A168068 this_sequence A163465 A004443 A171616` `Adjacent sequences: A163572 A163573 A163574 this_sequence A163576 A163577 A163578`
	KEYWORD	`nonn`
	AUTHOR	`Helmut Kreindl (euler(AT)chello.at), Jul 31 2009`

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

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