Permutation(?): + Integers Increasingly Arranged
Leroy Quet
qq-quet at mindspring.com
Sat Feb 21 01:26:15 CET 2004
>Yes, it is a permutation. We need to show that every space gets
>filled eventually. By induction, it is enough to prove that the
>left-most space gets filled eventually. We define a related sequence:
> When n is placed, let b(n) be the number of empty spaces to the left
>of n.
>This sequence obeys a recurrence:
> If b(n) >= n, b(n + 1) = b(n) - n;
> If b(n) < n, b(n + 1) = b(n) + n - 1.
>What we need to show is that this sequence will always eventually get
>back to 0.
>......
>...., so the sequence will always eventually
>get back to 0.
>
> - David Wasserman
>
Thanks for considering the sequence!
Has anybody calculated the sequence and/or its inverse to any number of
terms greater than I have?
Here is the sequence's definition again, for those who have deleted the
original email.
>a(1) = 1;
>
>And place the positive integers, once per integer, into the sequence so
>that:
>
>(m+1) is positioned in the sequence such that there are exactly (m-1)
>higher-valued terms between it and the term equal to m.
>And the (m+1) is always less than
[ie. to the left of]
>the m whenever this is possible.
>
>As to hopefully eliminate ambiguity, here is the arrangement of the first
>16 integers: (figured by-hand)
>
>1, 2, 13, 3, 6, *, 4, 11, *, 9, 5, * 7, *, *, *, *, *, *, 8,
> *, 10, 16, 12, *, 14, *, *, *, *, *, *, *, *, *, *, *, *, *, 15,...
>
>
>Of course, the *'s are yet to be determined and are each > 16.
And again, here is the inverse permutation's first few terms:
>1, 2, 4, 7, 11, 5, 13, 20, 10,...
thanks,
Leroy Quet
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