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

Author

Patrick De Geest, Sep 15 1999

Keywords

• nonn
• base

Examples

			9^33 = 30903154382632612361920641803529.
		

Crossrefs

Cf. A030705, A046267, A046275.

Programs

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 *)