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A005350
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a(1) = a(2) = a(3) = 1, a(n) = a(a(n-1))+a(n-a(n-1)) for n >= 4.
(Formerly M0253)
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3
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1, 1, 1, 2, 2, 3, 3, 3, 4, 5, 5, 5, 5, 6, 7, 7, 8, 8, 8, 8, 8, 9, 10, 11, 11, 12, 12, 12, 13, 13, 13, 13, 13, 13, 14, 15, 16, 16, 17, 18, 18, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 21, 21, 21, 22, 23, 24, 25, 25, 26, 27, 27, 28
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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COMMENTS
| a(n)-a(n-1) = 0 or 1 (see the 1991 Monthly reference). - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 06 2005
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REFERENCES
| R. K. Guy, The second strong law of small numbers. Math. Mag. 63 (1990), no. 1, 3-20.
Problem E3274, Amer. Math. Monthly, 98, No, 10, (1991), 958-959.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
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MAPLE
| A005350 := proc(n) option remember; if n<=3 then 1 else A005350(A005350(n-1))+A005350(n-A005350(n-1)); fi; end;
a[1]:=1: a[2]:=1: a[3]:=1: for n from 4 to 64 do a[n]:=a[a[n-1]]+a[n-a[n-1]] od: seq(a[n], n=1..64); (Deutsch)
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CROSSREFS
| Cf. A004001, A005707.
Sequence in context: A166079 A080677 A153112 * A055037 A125186 A140473
Adjacent sequences: A005347 A005348 A005349 * A005351 A005352 A005353
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KEYWORD
| nonn,easy,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), R. K. Guy
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