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A235775
a(n) = A047842(A047842(n)), say what you see, once repeated.
2
1011, 21, 1112, 1113, 1114, 1115, 1116, 1117, 1118, 1119, 1031, 1112, 3112, 3113, 3114, 3115, 3116, 3117, 3118, 3119, 102112, 3112, 22, 211213, 211214, 211215, 211216, 211217, 211218, 211219, 102113, 3113, 211213, 1213, 211314, 211315, 211316, 211317, 211318
OFFSET
0,1
COMMENTS
a(n) does not depend on the order of digits of n, a property inherited from A047842. - M. F. Hasler, Jan 11 2024
LINKS
FORMULA
From M. F. Hasler, Jan 11 2024: (Start)
a(n) = a(A328447(n)) = a(m) for all n and all m having the same digits as n, considering their respective multiplicity.
a(n) = A047842(n) =: m iff m is a fixed point of A047842. (End)
EXAMPLE
a(10) = A047842(1011) = 1031;
a(11) = A047842(21) = 1112;
a(12) = A047842(1112) = 3112;
a(100) = A047842(2011) = 102112;
a(101) = A047842(1021) = 102112;
a(102) = A047842(101112) = 104112.
For n = 20231231, digits of the date 2023-12-31, a(n) = 10213223 = A047842(n) because this is a fixed point of A047842. Since the order of the digits of n does not matter and there are no leading zeros, this holds also for the numbers resulting from notation dd.mm.yyyy or mm/dd/yyyy. - M. F. Hasler, Jan 11 2024
PROG
(Haskell)
a235775 = a047842 . a047842
(Python)
def A235775(n):
s = str(n)
s = ''.join(str(s.count(d))+d for d in sorted(set(s)))
return int(''.join(str(s.count(d))+d for d in sorted(set(s)))) # Chai Wah Wu, Feb 12 2023
(PARI) A235775(n) = A047842(A047842(n)) \\ M. F. Hasler, Jan 11 2024
CROSSREFS
Sequence in context: A266673 A055473 A317526 * A262865 A213315 A345906
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Jan 15 2014
STATUS
approved