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A050726
Decimal expansion of 5^n contains no pair of consecutive equal digits (probably finite).
1
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
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
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Sep 15 1999
STATUS
approved