A025690 Exponent of 10 (value of j) in n-th number of form 8^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, 0, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 10, 1, 11, 2, 3, 4, 5, 6, 7, 8, 9, 0, 10, 1, 11, 2, 12, 3, 4, 5, 6, 7, 8, 9, 0, 10, 1

Offset

1,6

Links

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

Formula

a(n) = A122840(A025634(n)). - Amiram Eldar, Nov 09 2025

Mathematica

seq[lim_] := IntegerExponent[Flatten[Table[8^i*10^j, {i, 0, Log[8, lim]}, {j, 0, Log10[lim/8^i]}]] // Sort, 10]; seq[10^13] (* Amiram Eldar, Nov 09 2025 *)

Crossrefs

Cf. A025634, A025677, A122840.

Sequence in context: A025659 A163351 A166352 * A025668 A373748 A048151

Adjacent sequences: A025687 A025688 A025689 * A025691 A025692 A025693

Keyword

nonn,easy

Author

David W. Wilson

Status

approved