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A137453
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a(0) = 2, a(1) = 9; thereafter, a(n) = a(n-1)*a(n-2) mod (a(n-1)+a(n-2)).
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0
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2, 9, 7, 15, 17, 31, 47, 53, 91, 71, 143, 95, 19, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| Comments from Jack Brennan (start):
Playing around with different starting pairs, it looks like all
starting pairs either end in a loop, or by going to the pair (0,0)
which is either a loop or a singularity, depending on whether you
take 0 mod 0 as being 0 or undefined. Furthermore, you can go
an arbitrarily long time without looping. Take for large a:
.., 6*a+6, 6*a, ...
The next term is 6*a-6, and progressively it goes down the
ladder by steps of 6 until it terminates at ..., 18, 12, 6, 0, 0.
In a few minutes of searching, the longest sequence I could find
which eventually loops without going to zero was the sequence
starting with (29,574), which hits 855 at the 79th term and then
stays at 855. (End)
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LINKS
| Eric Angelini, ModuloPlay [From Eric Angelini (eric.angelini(AT)skynet.be), Mar 13 2009]
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EXAMPLE
| 2*9 mod 2+9 = 18 mod 11 = 7.
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CROSSREFS
| Sequence in context: A157350 A121837 A160439 * A063381 A019078 A205384
Adjacent sequences: A137450 A137451 A137452 * A137454 A137455 A137456
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KEYWORD
| nonn
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AUTHOR
| Eric Angelini, Jul 07 2008
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EXTENSIONS
| More terms from Jack Brennen, Jul 07 2008
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