

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
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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 3digit strings 263 (0=26/3), 284 (0=28/4), 362 (0=36/2), 393 (39/3), 482 (0=48/2) are the only ones of the 9^3A288351(3)=274 3digit 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



