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A022514 Describe previous term from the right (method B - initial term is 3).

%I A022514 #15 Oct 06 2019 16:55:25
%S A022514 3,31,1131,113112,21123112,211231211221,112212211131211221,
%T A022514 1122122111311322112212,21112212223112311322112212,
%U A022514 21112212223112312112312311221321
%N A022514 Describe previous term from the right (method B - initial term is 3).
%C A022514 Method B = 'digit'-indication followed by 'frequency'.
%H A022514 Reinhard Zumkeller, <a href="/A022514/b022514.txt">Table of n, a(n) for n = 0..21</a>
%e A022514 The term after 1131 is obtained by saying "1 once, 3 once, 1 twice", which gives 113112.
%t A022514 A022514[1]:=3;A022514[n_]:=A022514[n]=FromDigits[Flatten[{First[#],Length[#]}&/@Split[Reverse[IntegerDigits[A022514[n-1]]]]]];Map[A022514,Range[15]] (* _Peter J. C. Moses_, Apr 22 2013 *)
%o A022514 (Haskell)
%o A022514 import Data.List (group, transpose)
%o A022514 a022514 n = a022514_list !! n
%o A022514 a022514_list = 3 : f [3] :: [Integer] where
%o A022514    f xs = (read $ concatMap show ys) : f ys where
%o A022514           ys = concat $ transpose [map head zss, map length zss]
%o A022514           zss = reverse $ group xs
%o A022514 -- _Reinhard Zumkeller_, Jan 26 2014
%Y A022514 Cf. A022481, A022488, A022515-A022520.
%K A022514 nonn,base,easy,nice
%O A022514 0,1
%A A022514 _N. J. A. Sloane_
%E A022514 More terms from _Patrick De Geest_, Jun 15 1999