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A173701
Let S be the sequence and let D denote the sequence obtained by moving every third term three steps to the left. The D is the sequence of absolute values of the first differences of S.
1
1, 3, 2, 5, 9, 4, 13, 19, 6, 25, 32, 7, 39, 47, 8, 55, 65, 10, 75, 86, 11, 97, 109, 12, 121, 135, 14, 149, 164, 15
OFFSET
1,2
COMMENTS
We also require that S be a permutation of the natural numbers and the lexicographically earliest sequence with the stated propoerty.
LINKS
E. Angelini, Hilbert Hotel and 3k rooms [Cached copy, with permission]
EXAMPLE
Here is S:
S = ...1,3,2,5,9,4,13,19,6,25,32,7,39,47,8,55,65,10,75,86,11,97,109,12,121
The terms 2,4,6,7, ... move 3 places left.
After the moves we have:
D = .2,1,3,4,5,9,6,13,19,7,25,32,8,39,47,10,55,65,11,75,86,12,97,109,14,121
and D indeed gives the absolute values of the first differences of S.
CROSSREFS
Sequence in context: A169755 A169748 A280875 * A116627 A254331 A210742
KEYWORD
nonn,more
AUTHOR
Eric Angelini, Nov 25 2010
STATUS
approved