A050730 Decimal expansion of 9^n contains no pair of consecutive equal digits (probably finite).

0, 1, 2, 3, 4, 5, 7, 8, 9, 11, 12, 13, 21, 33

Offset

0,3

Links

Table of n, a(n) for n=0..13.

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

Cf. A030705, A046267, A046275.

Sequence in context: A219301 A326155 A079734 * A288221 A346782 A229757

Adjacent sequences: A050727 A050728 A050729 * A050731 A050732 A050733

Keyword

nonn,base

Author

Patrick De Geest, Sep 15 1999

Status

approved