Running Modulus Recursions
Bruce Dearden and Jerry Metzger
University of North Dakota
Department of Mathematics
Witmer Hall Room 313
101 Cornell Street Stop 8376
Grand Forks ND 58202-8376
USA
Abstract:
Fix integers b ≥ 2 and k ≥ 1.
Define the sequence {zn}
recursively by taking z0 to be any integer,
and for n ≥ 1, taking
zn
to be the least nonnegative residue of bzn-1 modulo
(n+k). Since
the modulus increases by 1 when stepping from one term to the
next, such a definition will be called a running modulus recursion
or rumor for short. While the terms of such sequences
appear to bounce around irregularly, empirical evidence suggests
the terms will eventually be zero. We prove this is so when one
additional assumption is made, and we conjecture that this additional
condition is always met.
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Received December 2 2009;
revised version received January 12 2010.
Published in Journal of Integer Sequences, January 14 2010.
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