|
|
A050723
|
|
Numbers k such that the decimal expansion of 2^k contains no pair of consecutive equal digits (probably finite).
|
|
5
|
|
|
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 20, 21, 22, 28, 29, 30, 31, 32, 34, 35, 36, 37, 48, 54, 55, 56, 66, 67, 68, 69, 80, 87, 104, 126
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,3
|
|
COMMENTS
|
No further terms up to 100000. - T. D. Noe, Sep 18 2012
|
|
LINKS
|
|
|
EXAMPLE
|
2^126 = 85070591730234615865843651857942052864.
|
|
MAPLE
|
q:= n-> (s-> andmap(i-> s[i]<>s[i+1], [$1..length(s)-1]))(""||(2^n)):
|
|
MATHEMATICA
|
Select[Range[0, 10000], !MemberQ[Differences[IntegerDigits[2^#]], 0]&] (* Harvey P. Dale, Dec 24 2011 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|