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A244112 Reverse digit count of n in decimal representation. 8
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 1110, 21, 1211, 1311, 1411, 1511, 1611, 1711, 1811, 1911, 1210, 1211, 22, 1312, 1412, 1512, 1612, 1712, 1812, 1912, 1310, 1311, 1312, 23, 1413, 1513, 1613, 1713, 1813, 1913, 1410, 1411, 1412, 1413, 24, 1514, 1614, 1714 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Frequencies of digits 0 through 9, occurring in n, are summarized in order of decreasing digits;

a(A010785(n)) = A047842(A010785(n)).

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

EXAMPLE

101 contains two 1s and one 0, therefore a(101) = 2110;

102 contains one 2, one 1 and one 0, therefore a(102) = 121110.

MATHEMATICA

f[n_] := Block[{s = Split@ IntegerDigits@ n}, FromDigits@ Reverse@ Riffle[Union@ Flatten@ s, Length@# & /@ s]]; Array[f, 48, 0] (* Robert G. Wilson v, Dec 01 2016 *)

PROG

(Haskell)

import Data.List (sort, group); import Data.Function (on)

a244112 :: Integer -> Integer

a244112 n = read $ concat $

   zipWith ((++) `on` show) (map length xs) (map head xs)

   where xs = group $ reverse $ sort $ map (read . return) $ show n

(Python)

def A244112(n):

    return int(''.join([str(str(n).count(d))+d for d in '9876543210' if str(n).count(d) > 0])) # Chai Wah Wu, Dec 01 2016

(PARI) A244112(n, c=1, S="")={for(i=2, #n=vecsort(digits(n), , 4), n[i]==n[i-1]&&c++&&next; S=Str(S, c, n[i-1]); c=1); eval(Str(S, c, if(n, n[#n])))} \\ M. F. Hasler, Feb 25 2018

CROSSREFS

Cf. A047842, A010785.

See A036058 for the orbit of 0 under this map.

Sequence in context: A047843 A097598 A045918 * A088476 A248014 A304366

Adjacent sequences:  A244109 A244110 A244111 * A244113 A244114 A244115

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Nov 11 2014

STATUS

approved

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Last modified February 16 04:47 EST 2019. Contains 320140 sequences. (Running on oeis4.)