id:A072139 - OEIS Search Results

Search: id:A072139

Displaying 1-1 of 1 results found.

page 1

Last term of the preperiodic part of the 'Reverse and Subtract' trajectory of n, or -1 if the trajectory is completely periodic.

+0
3

-1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 11, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 22, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 33, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 44, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 55, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 66, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 77, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 88, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 99, 99, 101, 99 (list; graph; listen)

	OFFSET	`0,3`
	COMMENT	`'Reverse and Subtract' (cf. A072137) is defined by x -> \|x - reverse(x)\|. For small n the positive terms are the first palindrome in the trajectory of n, so this sequence is a weak analogue of A033865, which uses 'Reverse and Add'. a(1012) = 8712 is the first non-palindrome (cf. A072140). For k in A072140, A072141 or A072142 we have a(k) = -1.`
	EXAMPLE	`a(0) = -1, since 0 -> \|0 - 0\| = 0, the preperiodic part is empty; a(12) = 9, since 12 -> \|12 - 21\| = 9.`
	CROSSREFS	`Cf. A033865, A072137, A072140, A072141, A072142.` `Adjacent sequences: A072136 A072137 A072138 this_sequence A072140 A072141 A072142` `Sequence in context: A028904 A081600 A017884 this_sequence A122638 A090175 A010880`
	KEYWORD	`base,easy,sign`
	AUTHOR	`Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jun 24 2002`

page 1

Search completed in 0.002 seconds

Last modified October 10 20:39 EDT 2008. Contains 144831 sequences.

AT&T Labs Research