OFFSET
0,3
COMMENTS
The initial number counts as iteration 1.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 0..10000
FORMULA
PROG
(Python)
def A364682(n):
c = 1
while n not in {0, 1, 37, 58, 89, 145, 42, 20, 4, 16}:
n = sum((0, 1, 4, 9, 16, 25, 36, 49, 64, 81)[ord(d)-48] for d in str(n))
c += 1
return c
CROSSREFS
KEYWORD
nonn
AUTHOR
Chai Wah Wu, Aug 02 2023
STATUS
approved