

A288351


Number of strings of n digits from 1...9 such that no formula using the single digits in the given order exists that evaluates to 0.


7



9, 72, 455, 1500, 1014, 181, 1, 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

1,1


COMMENTS

For definitions and comments see A288350.
It is conjectured that a(n)=0 for n>=8.


LINKS



EXAMPLE

a(1)=9 because 1...9 /=0. a(2)=72, because only the 9 numbers 11, 22, ..., 99 of the 81 twodigit strings can represent 0.


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



