cp's OEIS Frontend

A235775 a(n) = A047842(A047842(n)), say what you see, once repeated.

%I A235775 #18 Jan 12 2024 22:45:25
%S A235775 1011,21,1112,1113,1114,1115,1116,1117,1118,1119,1031,1112,3112,3113,
%T A235775 3114,3115,3116,3117,3118,3119,102112,3112,22,211213,211214,211215,
%U A235775 211216,211217,211218,211219,102113,3113,211213,1213,211314,211315,211316,211317,211318
%N A235775 a(n) = A047842(A047842(n)), say what you see, once repeated.
%C A235775 a(n) does not depend on the order of digits of n, a property inherited from A047842. - _M. F. Hasler_, Jan 11 2024
%H A235775 Reinhard Zumkeller, <a href="/A235775/b235775.txt">Table of n, a(n) for n = 0..10000</a>
%F A235775 From _M. F. Hasler_, Jan 11 2024: (Start)
%F A235775 a(n) = a(A328447(n)) = a(m) for all n and all m having the same digits as n, considering their respective multiplicity.
%F A235775 a(n) = A047842(n) =: m iff m is a fixed point of A047842. (End)
%e A235775 a(10) = A047842(1011) = 1031;
%e A235775 a(11) = A047842(21) = 1112;
%e A235775 a(12) = A047842(1112) = 3112;
%e A235775 a(100) = A047842(2011) = 102112;
%e A235775 a(101) = A047842(1021) = 102112;
%e A235775 a(102) = A047842(101112) = 104112.
%e A235775 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
%o A235775 (Haskell)
%o A235775 a235775 = a047842 . a047842
%o A235775 (Python)
%o A235775 def A235775(n):
%o A235775     s = str(n)
%o A235775     s = ''.join(str(s.count(d))+d for d in sorted(set(s)))
%o A235775     return int(''.join(str(s.count(d))+d for d in sorted(set(s)))) # _Chai Wah Wu_, Feb 12 2023
%o A235775 (PARI) A235775(n) = A047842(A047842(n)) \\ _M. F. Hasler_, Jan 11 2024
%Y A235775 Cf. A047842, A328447.
%K A235775 nonn,base
%O A235775 0,1
%A A235775 _Reinhard Zumkeller_, Jan 15 2014