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A276692 Binary representations of n and n^2 have no common 3-digit substring. 1
0, 1, 2, 3, 5, 6, 7, 11, 23, 46, 85, 341, 1471, 2942, 5461, 21845, 349525, 1398101, 6025215, 12050430, 22369621, 89478485, 1431655765, 5726623061, 91625968981, 366503875925, 5864062014805, 23456248059221, 101086333501439, 202172667002878, 375299968947541, 1501199875790165 (list; graph; refs; listen; history; text; internal format)
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?

LINKS

Table of n, a(n) for n=1..32.

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

Cf. A177062.

Sequence in context: A071251 A077571 A101730 * A169829 A189208 A270974

Adjacent sequences:  A276689 A276690 A276691 * A276693 A276694 A276695

KEYWORD

nonn,base

AUTHOR

Robert Israel, Sep 13 2016

EXTENSIONS

a(27)-a(32) from Giovanni Resta, Aug 31 2019

STATUS

approved

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Last modified August 11 08:50 EDT 2020. Contains 336422 sequences. (Running on oeis4.)