MathDB
Problems
Contests
National and Regional Contests
USA Contests
MAA AMC
AIME Problems
1988 AIME Problems
2
Square of sum of digits
Square of sum of digits
Source:
March 17, 2006
function
Problem Statement
For any positive integer
k
k
k
, let
f
1
(
k
)
f_1(k)
f
1
(
k
)
denote the square of the sum of the digits of
k
k
k
. For
n
≥
2
n \ge 2
n
≥
2
, let
f
n
(
k
)
=
f
1
(
f
n
−
1
(
k
)
)
f_n(k) = f_1(f_{n - 1}(k))
f
n
(
k
)
=
f
1
(
f
n
−
1
(
k
))
. Find
f
1988
(
11
)
f_{1988}(11)
f
1988
(
11
)
.
Back to Problems
View on AoPS