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A099427
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a(1) = 1; for n > 1, a(n) = 1 + greatest common divisor of n and a(n-1).
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3
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1, 2, 2, 3, 2, 3, 2, 3, 4, 3, 2, 3, 2, 3, 4, 5, 2, 3, 2, 3, 4, 3, 2, 3, 2, 3, 4, 5, 2, 3, 2, 3, 4, 3, 2, 3, 2, 3, 4, 5, 2, 3, 2, 3, 4, 3, 2, 3, 2, 3, 4, 5, 2, 3, 2, 3, 4, 3, 2, 3, 2, 3, 4, 5, 6, 7, 2, 3, 4, 3, 2, 3, 2, 3, 4, 5, 2, 3, 2, 3, 4, 3, 2, 3, 2, 3, 4, 5, 2, 3, 2, 3, 4, 3, 2, 3, 2, 3, 4, 5, 2, 3, 2, 3, 4
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listen;
history;
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internal format)
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OFFSET
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1,2
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COMMENTS
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a(A060401(n)) = n + 1; a(A192489(n)) = 2; [Reinhard Zumkeller, Jul 02 2011]
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LINKS
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_Reinhard Zumkeller_, Table of n, a(n) for n = 1..10000
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EXAMPLE
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a(9)=4 because 1+gcd(a(8),9)=1+gcd(3,9)=1+3.
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MATHEMATICA
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a[1] = 1; a[n_] := a[n] = GCD[n, a[n - 1]] + 1; Table[ a[n], {n, 105}] (from Robert G. Wilson v Nov 18 2004)
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PROG
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(Haskell)
a099427 n = a099427_list !! (n-1)
a099427_list = 1 : f 2 1 where
f n x = x' : f (n+1) x' where x' = 1 + gcd n x
-- Reinhard Zumkeller, Jul 02 2011
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CROSSREFS
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For position of first occurrence of n see A060401.
Sequence in context: A073855 A077982 A185816 * A059964 A087458 A052180
Adjacent sequences: A099424 A099425 A099426 * A099428 A099429 A099430
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KEYWORD
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easy,nonn,nice
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AUTHOR
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Gaetan Polard (gaetan27(AT)hotmail.com), Nov 18 2004
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EXTENSIONS
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Edited and extended by Robert G. Wilson v, Nov 18 2004
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STATUS
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approved
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