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Search: id:A022440
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| A022440 |
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a(n) = c(n-1) + c(n-3) where c is the sequence of positive numbers not in a. |
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+0
1
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| 3, 4, 5, 7, 10, 15, 19, 21, 24, 26, 29, 31, 34, 37, 40, 43, 47, 50, 53, 57, 60, 63, 67, 69, 73, 75, 79, 81, 85, 87, 90, 93, 95, 99, 101, 105, 107, 110, 113, 115, 119, 121, 125, 127, 130, 133
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Comment from N. J. A. Sloane (njas(AT)research.att.com), Nov 24, 2004: I'm not sure of the minimal hypotheses needed to generate this sequence, but one method that works is the following:
Start with a(1)=3, a(2)=4, a(3)=5, so that we know c(1)=1 and c(2)=2. Let c(3) = x >= 6, so that a(4) = 1+x >= 6 and x=6 is forced, with a(4)=7. Then c(4) >= 8, a(5) >= 10, so definitely c(4)=8 and c(5)=9. From now on the sequence extends easily.
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CROSSREFS
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Sequence in context: A073957 A162311 A003312 this_sequence A088130 A046840 A057773
Adjacent sequences: A022437 A022438 A022439 this_sequence A022441 A022442 A022443
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KEYWORD
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nonn,easy,more
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AUTHOR
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Clark Kimberling (ck6(AT)evansville.edu)
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