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A051013
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Number of nonaveraging sequences on {1,2,...,n}.
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3
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1, 2, 4, 7, 13, 23, 40, 65, 106, 169, 278, 443, 705, 1117, 1760, 2692, 4151, 6314, 9526, 14127, 20944, 30848, 45589, 66495, 96847, 140840, 204380, 293822, 425859, 613446, 880288, 1258349, 1794256, 2545965, 3623774, 5123746, 7207773, 10159163, 14273328, 19925242, 27893419
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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LINKS
| Eric Weisstein's World of Mathematics, Nonaveraging Sequence
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EXAMPLE
| The only subset of s = {1,2,3} that contains a 3-term arithmetic progression is s itself, so a(3) = 7.
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CROSSREFS
| Sequence in context: A054150 A130709 A073832 * A128609 A168043 A114832
Adjacent sequences: A051010 A051011 A051012 * A051014 A051015 A051016
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KEYWORD
| nonn
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AUTHOR
| Eric Weisstein (eric(AT)weisstein.com)
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EXTENSIONS
| More terms from John W. Layman (layman(AT)math.vt.edu), Nov 27 2001
a(29)-a(37) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Aug 15 2010
A(38)-a(40) from Alois P. Heinz (heinz(AT)hs-heilbronn.de), Oct 27 2011
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