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Search: id:A081461
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| A081461 |
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Consider the mapping f(a/b) = (a^2+b^3)/(a^3+b^2) from rationals to rationals. Starting with 1/2 (a=1, b=2) and applying the mapping to each new (reduced) rational number gives 1/2, 9/5, 103/377, ... . Sequence gives values of the numerators. |
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+0
4
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| 1, 9, 103, 26796621, 236092315725004393, 3561970421302126514421966146019939188025056477849165490630219227287
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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For the mapping g(a/b) = (a^2+b)/(a+b^2), starting with 1/2 the same procedure leads to the periodic sequence 1/2, 3/5, 1/2, 3/5, ...
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PROGRAM
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(PARI) {r=1/2; for(n=1, 7, a=numerator(r); b=denominator(r); print1(a, ", "); r=(a^2+b^3)/(a^3+b^2))}
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CROSSREFS
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Cf. A000058, A081462, A081463, A081465.
Adjacent sequences: A081458 A081459 A081460 this_sequence A081462 A081463 A081464
Sequence in context: A101563 A007133 A083452 this_sequence A110698 A012485 A052503
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 22 2003
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EXTENSIONS
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Edited and extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Mar 28 2003
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