A050726 Decimal expansion of 5^n contains no pair of consecutive equal digits (probably finite).

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 14, 15, 16, 17, 18, 19, 20, 21, 22, 27, 28, 29, 32

Offset

0,3

Comments

No further terms up to 3000. - Harvey P. Dale, May 11 2011

No further terms up to 80000. - Ivan N. Ianakiev, Aug 31 2019

Links

Table of n, a(n) for n=0..23.

Example

5^32 = 23283064365386962890625.

Maple

q:= n-> (s-> andmap(i-> s[i]<>s[i+1], [$1..length(s)-1]))(""||(5^n)):
select(q, [$0..200])[];  # Alois P. Heinz, Mar 07 2024

Mathematica

Select[Range[0, 3000], And@@(First[#]!=Last[#]&/@Partition[ IntegerDigits[ 5^#], 2, 1])&] (* Harvey P. Dale, May 11 2011 *)
Select[Range[0, 40], SequenceCount[IntegerDigits[5^#], {x_, x_}]==0&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 12 2020 *)

Crossrefs

Cf. A008839, A046263, A046271.

Sequence in context: A263443 A266352 A247144 * A108155 A134932 A134933

Adjacent sequences: A050723 A050724 A050725 * A050727 A050728 A050729

Keyword

nonn,base

Author

Patrick De Geest, Sep 15 1999

Status

approved