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A288352 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. 3
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

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.

LINKS

Table of n, a(n) for n=1..80.

EXAMPLE

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.

CROSSREFS

Cf. A288350, A288351, A288502, A288550.

Sequence in context: A229414 A210923 A229524 * A301949 A316709 A293953

Adjacent sequences:  A288349 A288350 A288351 * A288353 A288354 A288355

KEYWORD

nonn

AUTHOR

Hugo Pfoertner, Jun 10 2017

STATUS

approved

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Last modified January 28 12:38 EST 2022. Contains 350656 sequences. (Running on oeis4.)