<s>
In	O
recreational	O
mathematics	O
,	O
a	O
Keith	B-Algorithm
number	I-Algorithm
or	O
repfigit	B-Algorithm
number	I-Algorithm
(	O
short	O
for	O
repetitive	O
Fibonacci-like	O
digit	O
)	O
is	O
a	O
natural	O
number	O
in	O
a	O
given	O
number	O
base	O
with	O
digits	O
such	O
that	O
when	O
a	O
sequence	O
is	O
created	O
such	O
that	O
the	O
first	O
terms	O
are	O
the	O
digits	O
of	O
and	O
each	O
subsequent	O
term	O
is	O
the	O
sum	O
of	O
the	O
previous	O
terms	O
,	O
is	O
part	O
of	O
the	O
sequence	O
.	O
</s>
<s>
Keith	B-Algorithm
numbers	I-Algorithm
were	O
introduced	O
by	O
Mike	O
Keith	O
in	O
1987	O
.	O
</s>
<s>
If	O
there	O
exists	O
an	O
such	O
that	O
,	O
then	O
is	O
said	O
to	O
be	O
a	O
Keith	B-Algorithm
number	I-Algorithm
.	O
</s>
<s>
Whether	O
or	O
not	O
there	O
are	O
infinitely	O
many	O
Keith	B-Algorithm
numbers	I-Algorithm
in	O
a	O
particular	O
base	O
is	O
currently	O
a	O
matter	O
of	O
speculation	O
.	O
</s>
<s>
Keith	B-Algorithm
numbers	I-Algorithm
are	O
rare	O
and	O
hard	O
to	O
find	O
.	O
</s>
<s>
According	O
to	O
Keith	O
,	O
in	O
base	O
10	O
,	O
on	O
average	O
Keith	B-Algorithm
numbers	I-Algorithm
are	O
expected	O
between	O
successive	O
powers	O
of	O
10	O
.	O
</s>
<s>
In	O
base	O
2	O
,	O
there	O
exists	O
a	O
method	O
to	O
construct	O
all	O
Keith	B-Algorithm
numbers	I-Algorithm
.	O
</s>
<s>
A	O
Keith	O
cluster	O
is	O
a	O
related	O
set	O
of	O
Keith	B-Algorithm
numbers	I-Algorithm
such	O
that	O
one	O
is	O
a	O
multiple	O
of	O
another	O
.	O
</s>
<s>
The	O
example	O
below	O
implements	O
the	O
sequence	O
defined	O
above	O
in	O
Python	B-Language
to	O
determine	O
if	O
a	O
number	O
in	O
a	O
particular	O
base	O
is	O
a	O
Keith	B-Algorithm
number	I-Algorithm
:	O
</s>
