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A060723
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a(n) is the denominator of b(n) where b(n) is a sequence of rational numbers defined by the recursion: b(0) = 0, b(1) = 1 and for n>1 b(n) = b(n-1) + b(n-2)/2 . By this definition it is clear that a(n) is always a power of 2 (see A060755).
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1
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1, 1, 1, 2, 1, 4, 4, 8, 1, 16, 16, 32, 8, 64, 64, 128, 8, 256, 256, 512, 128, 1024, 1024, 2048, 256, 4096, 4096, 8192, 2048, 16384, 16384, 32768, 1024, 65536, 65536, 131072, 32768, 262144, 262144, 524288, 65536, 1048576, 1048576, 2097152
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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EXAMPLE
| The sequence b(n) begins 0, 1, 1, 3/2, 2, 11/4, 15/4, 41/8, 7, 153/16, 209/16, 571/32, 363/16, 2023/64, 2749/64, 7521/128, 5135/64, ... It can be proved that b(n) is an integer (i.e. a(n) = 1) iff n is one of 0, 1, 2, 4, 8.
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CROSSREFS
| Cf. A060755.
Sequence in context: A077965 A077967 A008312 * A195691 A074763 A099932
Adjacent sequences: A060720 A060721 A060722 * A060724 A060725 A060726
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KEYWORD
| nonn,easy
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AUTHOR
| Avi Peretz (njk(AT)netvision.net.il), Apr 21 2001
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EXTENSIONS
| More terms from Vladeta B. Jovovic (vladeta(AT)eunet.rs), Apr 24 2001
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