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A003667
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a(n) is smallest number which is uniquely of the form a(j)+a(k) with 1<=j<k<n.
(Formerly M3746)
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5
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1, 5, 6, 7, 8, 9, 10, 12, 20, 22, 23, 24, 26, 38, 39, 40, 41, 52, 57, 69, 70, 71, 82, 87, 98, 102, 113, 119, 129, 130, 133, 144, 160, 161, 162, 163, 175, 196, 205, 208, 209, 222, 223, 224, 226, 237, 253, 254, 255, 256, 268, 269, 270, 271, 272, 284, 285, 286, 303, 318
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| An Ulam-type sequence - see A002858 for many further references, comments, etc.
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REFERENCES
| R. K. Guy, ``s-Additive sequences,'' preprint, 1994.
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..10000
S. R. Finch, Patterns in 1-additive sequences, Experimental Mathematics 1 (1992), 57-63.
Eric Weisstein's World of Mathematics, Ulam Sequence
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PROG
| (Haskell)
a003667 n = a003667_list !! (n-1)
a003667_list = 1 : 5 : ulam 2 5 a003667_list
-- Function ulam as defined in A002858.
-- Reinhard Zumkeller, Nov 03 2011
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CROSSREFS
| Sequence in context: A172072 A121542 A023379 * A138469 A089362 A121537
Adjacent sequences: A003664 A003665 A003666 * A003668 A003669 A003670
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Mira Bernstein
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