A025691 Exponent of 10 (value of j) in n-th number of form 9^i*10^j.

0, 0, 1, 0, 1, 2, 0, 1, 2, 3, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11

Offset

1,6

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A122840(A025635(n)). - Amiram Eldar, Nov 09 2025

Mathematica

seq[lim_] := IntegerExponent[Flatten[Table[9^i*10^j, {i, 0, Log[9, lim]}, {j, 0, Log10[lim/9^i]}]] // Sort, 10]; seq[10^13] (* Amiram Eldar, Nov 09 2025 *)

Crossrefs

Cf. A025635, A025683, A122840.

Differs from A002262 at a(253).

Sequence in context: A048151 A025675 A025682 * A002262 A374448 A298486

Adjacent sequences: A025688 A025689 A025690 * A025692 A025693 A025694

Keyword

nonn,easy

Author

David W. Wilson

Status

approved