A244112 Reverse digit count of n in decimal representation.

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

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