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A288352
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Number of strings of n digits from 1..9 such that a formula using the single digits in the given order with result 0 needs at least one division.
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3
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0, 0, 5, 168, 659, 163, 14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
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OFFSET
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1,3
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COMMENTS
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For definitions see A288350. An exhaustive computation for the 9^8 strings of 8 digits confirms that for all of them formulas avoiding divisions exist. a(8) = 0 implies that a(n) = 0 for n > 8.
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LINKS
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Table of n, a(n) for n=1..80.
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EXAMPLE
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a(3)=5, because the 5 3-digit strings 263 (0=2-6/3), 284 (0=2-8/4), 362 (0=3-6/2), 393 (3-9/3), 482 (0=4-8/2) are the only ones of the 9^3-A288351(3)=274 3-digit strings for which a formula with result 0 exists that cannot avoid including a division.
A288502 provides a list of all strings with this property.
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CROSSREFS
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Cf. A288350, A288351, A288502, A288550.
Sequence in context: A229414 A210923 A229524 * A301949 A316709 A293953
Adjacent sequences: A288349 A288350 A288351 * A288353 A288354 A288355
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KEYWORD
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nonn
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AUTHOR
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Hugo Pfoertner, Jun 10 2017
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STATUS
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approved
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