A139337 Replace each digit with its number of occurrences in decimal representation of n.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 22, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 22, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 22, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 22, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 22, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 22, 11, 11, 11, 11, 11, 11

Offset: 0

Author

Reinhard Zumkeller, Apr 14 2008

Keywords

• nonn
• base
• look

Comments

A055642(a(n)) = A055642(n) for n < (10^10-1)/9; fixed points: a(A108571(n)) = A108571(n).

Examples

			a(373) = 212, since, reading the digits of 373 from left to right, 3 appeared twice, 7 once, 3 twice.
		

Links

• R. Zumkeller, Table of n, a(n) for n = 0..25000

Programs

Haskell

import Data.List (group, sort); import Data.Maybe (mapMaybe)
a139337 n = read $ concatMap show $ mapMaybe (flip lookup ls) ds :: Int
   where ls = zip (map head zss) (map length zss)
         zss = group $ sort ds
         ds = map (read . return) $ show n :: [Int]
-- Reinhard Zumkeller, Mar 14 2014

Mathematica

a[n_] := IntegerDigits[n] /. Thread[{1, 2, 3, 4, 5, 6, 7, 8, 9, 0} -> DigitCount[n]] // FromDigits; Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Nov 28 2013 *)