A190598 Maximal digit in base-9 expansion of n.

0, 1, 2, 3, 4, 5, 6, 7, 8, 1, 1, 2, 3, 4, 5, 6, 7, 8, 2, 2, 2, 3, 4, 5, 6, 7, 8, 3, 3, 3, 3, 4, 5, 6, 7, 8, 4, 4, 4, 4, 4, 5, 6, 7, 8, 5, 5, 5, 5, 5, 5, 6, 7, 8, 6, 6, 6, 6, 6, 6, 6, 7, 8, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 1, 1, 2, 3, 4, 5, 6, 7, 8, 1, 1, 2, 3, 4, 5, 6, 7, 8, 2, 2, 2, 3, 4, 5

Offset: 0

Author

N. J. A. Sloane, May 13 2011

Keywords

• nonn
• base
• easy

Crossrefs

Cf. A007095 (base 9), A033046 (indices of 1's), A338090 (indices of 8's).

Cf. A054055 (maximal digit in decimal).

Programs

Mathematica

a[n_] := Max[IntegerDigits[n, 9]]; (* Matej Veselovac, Jul 23 2021 *)

PARI

a(n) = if (n, vecmax(digits(n, 9)), 0); \\ Michel Marcus, Jul 19 2020

Python

from sympy.ntheory.digits import digits
def a(n): return max(digits(n, 9)[1:])
print([a(n) for n in range(105)]) # Michael S. Branicky, Jul 23 2021

Formula

From Matej Veselovac, Jul 23 2021: (Start)

a(n) = 1 iff n is in A033046.

a(n) = 8 iff n is in A338090. (End)