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

3, 31, 1131, 113112, 21123112, 211231211221, 112212211131211221, 1122122111311322112212, 21112212223112311322112212, 21112212223112312112312311221321

Offset

0,1

Comments

Method B = 'digit'-indication followed by 'frequency'.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 0..21

Example

The term after 1131 is obtained by saying "1 once, 3 once, 1 twice", which gives 113112.

Mathematica

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 *)

Prog

(Haskell)
import Data.List (group, transpose)
a022514 n = a022514_list !! n
a022514_list = 3 : f [3] :: [Integer] where
   f xs = (read $ concatMap show ys) : f ys where
          ys = concat $ transpose [map head zss, map length zss]
          zss = reverse $ group xs
-- Reinhard Zumkeller, Jan 26 2014

Crossrefs

Cf. A022481, A022488, A022515-A022520.

Sequence in context: A356673 A274592 A219266 * A094579 A029729 A319253

Adjacent sequences: A022511 A022512 A022513 * A022515 A022516 A022517

Keyword

nonn,base,easy,nice

Author

N. J. A. Sloane

Extensions

More terms from Patrick De Geest, Jun 15 1999

Status

approved