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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
OFFSET
1,1
COMMENTS
For definitions and comments see A288350.
It is conjectured that a(n)=0 for n>=8.
The conjecture is true, as shown in the corresponding comment in A288350. - Hugo Pfoertner, Jun 09 2017
EXAMPLE
a(1)=9 because 1...9 /=0. a(2)=72, because only the 9 numbers 11, 22, ..., 99 of the 81 two-digit strings can represent 0.
CROSSREFS
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Jun 08 2017
STATUS
approved