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Search: id:A003407
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| A003407 |
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Number of permutations with no 3-term arithmetic progression.
(Formerly M1201)
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+0
2
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| 1, 2, 4, 10, 20, 48, 104, 282, 496, 1066, 2460, 6128, 12840, 29380, 74904, 212728, 368016, 659296, 1371056, 2937136
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
R. C. Entringer and D. E. Lackson, Problem E2440, Amer. Math. Monthly, 82 (1975), 74-77.
P. Erdos and P. Turan, On some sequences of integers, J. London Math. Soc., 11 (1936), 261-264.
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CROSSREFS
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Sequence in context: A026666 A121880 A094536 this_sequence A151523 A026395 A090246
Adjacent sequences: A003404 A003405 A003406 this_sequence A003408 A003409 A003410
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KEYWORD
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nonn,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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