A390767 Number of digits in base-9 representation of n.

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3

Offset

0,10

Links

Paolo Xausa, Table of n, a(n) for n = 0..10000

Formula

a(n) = floor(log_9(n)) + 1, for n >= 1.

Example

a(1000) = 4 because 1000 = 1331_9 (4 digits).

Mathematica

A390767[n_] := If[n == 0, 1, IntegerLength[n, 9]];
Array[A390767, 100, 0]

Crossrefs

Cf. analogous sequences for other bases: A070939 (base 2), A081604 (base 3), A110591 (base 4), A110592 (base 5), A390764 (base 6), A390765 (base 7), A390766 (base 8), A055642 (base 10).

Cf. A007095.

Sequence in context: A276502 A138902 A211668 * A255270 A211670 A036452

Adjacent sequences: A390764 A390765 A390766 * A390768 A390769 A390770

Keyword

nonn,base,easy

Author

Paolo Xausa, Nov 18 2025

Status

approved