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A008336
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a(n+1) = a(n)/n if n|a(n) else a(n)*n, a(1) = 1.
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6
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1, 1, 2, 6, 24, 120, 20, 140, 1120, 10080, 1008, 11088, 924, 12012, 858, 12870, 205920, 3500640, 194480, 3695120, 184756, 3879876, 176358, 4056234, 97349616, 2433740400, 93605400, 2527345800
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| The graph of log_10(a(n)+1) seems to suggest that
log(a(n)) is asymptotic to C*n
where C is approximately 0.8 - Daniel Forgues, Sept 18 2011
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REFERENCES
| R. K. Guy and R. Nowakowski, Unsolved Problems, Amer. Math. Monthly, vol. 102 (1995), circa page 924.
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
N. J. A. Sloane, My favorite integer sequences, in Sequences and their Applications (Proceedings of SETA '98).
Index entries for sequences related to Recaman's sequence
Nick Hobson, Python program for this sequence
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MAPLE
| A008336 := proc(n) option remember; if n = 1 then 1 elif A008336(n-1) mod (n-1) = 0 then A008336(n-1)/(n-1) else A008336(n-1)*(n-1); fi; end;
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MATHEMATICA
| a[n_] := a[n] = If[ Divisible[ a[n-1], n-1], a[n-1]/(n-1), a[n-1]*(n-1)]; a[1] = 1; Table[a[n], {n, 1, 28}] (* From Jean-François Alcover, Dec 02 2011 *)
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PROG
| Contribution from Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 25 2010: (Start)
(Other) Haskell:
(/*) x y = if x `mod` y == 0 then x `div` y else x*y
a008336 n = foldl (/*) 1 [2..n-1]
-- eop. (End)
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CROSSREFS
| Cf. A005132, A065422.
Cf. A195504 Product of numbers up to n-1 used as divisors in A008336(n), n >= 2; a(1) = 1.
Sequence in context: A092495 A110808 A065422 * A033643 A050211 A066616
Adjacent sequences: A008333 A008334 A008335 * A008337 A008338 A008339
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KEYWORD
| nonn,easy,nice
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AUTHOR
| B. Recaman [Recam\'{a}n].
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