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Bulgarian Spring Mathematical Competition
2023 Bulgarian Spring Mathematical Competition
11.3
11.3
Part of
2023 Bulgarian Spring Mathematical Competition
Problems
(1)
Positive integers representable as sum and difference of powers of 2
Source: Bulgarian Spring Tournament 2023 11.3
3/25/2023
A positive integer
b
b
b
is called good if there exist positive integers
1
=
a
1
,
a
2
,
…
,
a
2023
=
b
1=a_1, a_2, \ldots, a_{2023}=b
1
=
a
1
,
a
2
,
…
,
a
2023
=
b
such that
∣
a
i
+
1
−
a
i
∣
=
2
i
|a_{i+1}-a_i|=2^i
∣
a
i
+
1
−
a
i
∣
=
2
i
. Find the number of the good integers.
number theory