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A064657
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a(n) = a(|n - a(n-3)|) + a(|n - a(n-4)|) for n > 3, a(n)=1 otherwise.
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3
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1, 1, 1, 1, 2, 4, 8, 12, 10, 5, 2, 2, 13, 12, 26, 13, 3, 9, 14, 11, 11, 25, 12, 26, 13, 13, 27, 27, 26, 4, 2, 6, 34, 10, 60, 5, 28, 53, 22, 62, 25, 24, 22, 25, 22, 51, 38, 25, 28, 3, 26, 53, 16, 53, 27, 63, 26, 4, 10, 12, 86, 57, 42, 79, 24, 36, 25, 38, 56, 32, 85, 23
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,5
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COMMENTS
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LINKS
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EXAMPLE
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Last term: a(866) = a(|866 - a(866-3)|) + a(|866 - a(866-4)|) = a(|866 - a(863)|) + a(|866 - a(862)|) = a(|866 - 718|) + a(|866 - 88|) = a(148) + a(778) = 28 + 655 = 683,
but a(867) = a(|867 - a(867-3)|) + a(|867 - a(867-4)|) = a(|867 - a(864)|) + a(|867 - a(863)|) = a(|867 - 2546|) + a(|867 - 718|) = a(1679) + a(149) = undefined + 112 = undefined.
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PROG
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(Haskell)
a064657 n = a064657_list !! n
a064657_list = map fromJust $ takeWhile (/= Nothing) zs where
z n = fromJust $ zs !! n
zs = (map Just [1, 1, 1, 1]) ++ f 4 where
f x = y : f (x + 1) where
y | 2*x < max i3 i4 = Nothing
| otherwise = Just $ z (abs (x - i3)) + z (abs (x - i4))
where i3 = z (x - 3); i4 = z (x - 4)
b064657 = bFile' "A064657" a064657_list 0 -- (0.03 secs, 3184228 bytes)
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CROSSREFS
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KEYWORD
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nonn,fini,full
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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