A067898 Least digit not used in n (or 10 if n is pandigital).

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, 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, 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

Offset: 0

Author

Rick L. Shepherd, May 13 2003

Keywords

• base
• easy
• nonn

Comments

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

a(A052382(n)) = 0; a(A011540(n)) > 0. [Reinhard Zumkeller, May 04 2012]

Examples

			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.
		

Links

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

Crossrefs

Cf. A050278 (pandigital numbers).

Cf. A212193 (ternary).

Programs

Haskell

import Data.List (delete)
a067898 n = f n [0..10] where
   f x ys | x <= 9    = head $ delete x ys
          | otherwise = f x' $ delete d ys where (x',d) = divMod x 10
-- Reinhard Zumkeller, May 04 2012

Python

def A067898(n):
    s = set(str(n))
    for i in range(10):
        if str(i) not in s:
            return i
    return 10 # Chai Wah Wu, Apr 13 2024