%I #18 Apr 13 2024 22:52:35

%S 1,0,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,

%T 0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,

%U 0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,2,2,3,2,2

%N Least digit not used in n (or 10 if n is pandigital).

%C a(A050278(1)) = a(1023456789) = 10, the first term with that value, as 1023456789 is the first base 10 pandigital number.

%C a(A052382(n)) = 0; a(A011540(n)) > 0. [_Reinhard Zumkeller_, May 04 2012]

%H Reinhard Zumkeller, <a href="/A067898/b067898.txt">Table of n, a(n) for n = 0..10000</a>

%e a(10)=2 because decimal digits 0 and 1 are both used in 10, a(102)=3 because decimal digits 0, 1 and 2 are used in 102.

%o (Haskell)

%o import Data.List (delete)

%o a067898 n = f n [0..10] where

%o f x ys | x <= 9 = head $ delete x ys

%o | otherwise = f x' $ delete d ys where (x',d) = divMod x 10

%o -- _Reinhard Zumkeller_, May 04 2012

%o (Python)

%o def A067898(n):

%o s = set(str(n))

%o for i in range(10):

%o if str(i) not in s:

%o return i

%o return 10 # _Chai Wah Wu_, Apr 13 2024

%Y Cf. A050278 (pandigital numbers).

%Y Cf. A212193 (ternary).

%K base,easy,nonn

%O 0,11

%A _Rick L. Shepherd_, May 13 2003