A048321 - OEIS

%I #12 Apr 23 2019 12:39:17

%S 0,1,2,3,4,5,6,7,8,9,11,22,33,44,55,66,77,88,99,110,111,112,113,114,

%T 115,116,117,118,119,220,221,222,223,224,225,226,227,228,229,330,331,

%U 332,333,334,335,336,337,338,339,440,441,442,443,444,445,446,447,448

%N Reading a(n) expansion from left to right, run lengths strictly decrease.

%H Reinhard Zumkeller, <a href="/A048321/b048321.txt">Table of n, a(n) for n = 1..10000</a>

%o (Haskell)

%o import Data.List (group)

%o a048321 n = a048321_list !! (n-1)

%o a048321_list = filter f [0..] where

%o    f x = all (< 0) $ zipWith (-) (tail zs) zs

%o          where zs =  map length $ group $ show x

%o -- _Reinhard Zumkeller_, May 01 2015

%Y Cf. A037013, A043636, A043713, A044821, A044959.

%K nonn,base

%O 1,3

%A _Patrick De Geest_, Feb 15 1999