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A050730
Decimal expansion of 9^n contains no pair of consecutive equal digits (probably finite).
1
0, 1, 2, 3, 4, 5, 7, 8, 9, 11, 12, 13, 21, 33
OFFSET
0,3
EXAMPLE
9^33 = 30903154382632612361920641803529.
MAPLE
q:= n-> (s-> andmap(i-> s[i]<>s[i+1], [$1..length(s)-1]))(""||(9^n)):
select(q, [$0..200])[]; # Alois P. Heinz, Mar 07 2024
MATHEMATICA
Select[Range[0, 350], FreeQ[Differences[IntegerDigits[9^#]], 0]&] (* Harvey P. Dale, Sep 16 2024 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Sep 15 1999
STATUS
approved