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Search: id:A081480
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| A081480 |
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Consider the mapping f(a/b) = (a^2 +b^2)/(a+b). Taking a =1, b = 2 to start with, and carrying out this mapping repeatedly on each new (reduced) rational number gives the following sequence 1/2,5/3,17/4,305/21,... Sequence contains the denominators. |
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2
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| 2, 3, 4, 21, 163, 23448, 1092023377, 596231923288918561, 355492505697703670063523236830811569, 126374921607231876111985200006557923908784362170241984606666354067170697
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OFFSET
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1,1
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COMMENT
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The mapping f(a/b) = (a + b)/(a - b). Taking a = 2 b = 1 to start with, and carrying out this mapping repeatedly on each new (reduced)rational number gives the periodic sequence 2/1,3/1,2/1,3/1,...
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CROSSREFS
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Cf. A081479.
Sequence in context: A058780 A109787 A109302 this_sequence A070841 A069801 A019074
Adjacent sequences: A081477 A081478 A081479 this_sequence A081481 A081482 A081483
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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 24 2003
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EXTENSIONS
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More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 06 2003
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