A116667 Greatest digit not used in n (or 10 if n is pandigital).

9, 9, 9, 9, 9, 9, 9, 9, 9, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 7, 8, 8, 8, 8, 8, 8, 8, 8, 7, 8, 9, 9, 9, 9, 9

Offset: 0

Author

Rick L. Shepherd, Feb 22 2006

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.

Examples

			a(89) = 7 because decimal digits 8 and 9 are both used in 89.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A067898 (least digit not used in n), A050278 (pandigital numbers).

Programs

Python

def A116667(n):
    s = set(str(n))
    for i in range(9,-1,-1):
        if str(i) not in s:
            return i
    return 10 # Chai Wah Wu, Apr 13 2024