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National and Regional Contests
Argentina Contests
Argentina National Olympiad
2000 Argentina National Olympiad
5
5
Part of
2000 Argentina National Olympiad
Problems
(1)
computer divides with 18
Source: Argentina 2000 OMA L3 p4
5/12/2024
A computer program generates a sequence of numbers with the following rule: the first number is written by Camilo; thereafter, the program calculates the integer division of the last number generated by
18
18
18
; thus obtains a quotient and a remainder. The sum of that quotient plus that remainder is the next number generated. For example, if Camilo's number is
5291
,
5291,
5291
,
the computer makes
5291
=
293
×
18
+
17
5291 = 293 \times 18 + 17
5291
=
293
×
18
+
17
, and generates
310
=
293
+
17
310 = 293 + 17
310
=
293
+
17
. The next number generated will be
21
21
21
, since
310
=
17
×
18
+
4
310 = 17 \times 18 + 4
310
=
17
×
18
+
4
and
17
+
4
=
21
17 + 4= 21
17
+
4
=
21
; etc Whatever Camilo's initial number is, from some point on, the computer always generates the same number. Determine what is that number that will be repeated indefinitely, if Camilo's initial number is equal to
2
110
.
2^{110}.
2
110
.
number theory