OFFSET
1,3
COMMENTS
n such that A177062(n) <= 2.
Contains (4^m-1)/3 for m not divisible by 3.
Contains 2^(3*2^(k-1)-1) - 1 - Sum_{j=1..k-1} 2^(3*(2^(k-1)-2^(j-1))) and 2^(3*2^(k-1)) - 2 - Sum_{j=1..k-1} 2^(3*(2^(k-1)-2^(j-1))+1) for all k>=1.
Are there any other terms besides these and 0, 2, 7, 11?
EXAMPLE
The binary representations of 11 and 11^2 are 1011 and 1111001. The 3-digit substrings 101 and 011 of 1011 are not substrings of 1111001, so 11 is in the sequence.
MAPLE
f:= n -> length(StringTools:-LongestCommonSubString(convert(convert(n, binary), string), convert(convert(n^2, binary), string))):
select(f <= 2, [$0..1000]);
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Robert Israel, Sep 13 2016
EXTENSIONS
a(27)-a(32) from Giovanni Resta, Aug 31 2019
STATUS
approved