

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
(list;
graph;
refs;
listen;
history;
text;
internal format)



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


LINKS

Table of n, a(n) for n=1..78.


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

Cf. A288350, A288352, A288353, A288354, A288355, A288356.
Sequence in context: A070823 A073988 A005778 * A319892 A319873 A110396
Adjacent sequences: A288348 A288349 A288350 * A288352 A288353 A288354


KEYWORD

nonn


AUTHOR

Hugo Pfoertner, Jun 08 2017


STATUS

approved



