A025684 Exponent of 10 (value of j) in n-th number of form 2^i*10^j.

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

Offset

1,12

Links

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

Formula

a(n) = A122840(A025612(n)). - Amiram Eldar, Nov 09 2025

Mathematica

seq[lim_] := IntegerExponent[Flatten[Table[2^i*10^j, {i, 0, Log2[lim]}, {j, 0, Log10[lim/2^i]}]] // Sort, 10]; seq[10^8] (* Amiram Eldar, Nov 09 2025 *)

Crossrefs

Cf. A025612, A025639, A122840.

Sequence in context: A025858 A237451 A215592 * A025678 A073189 A194519

Adjacent sequences: A025681 A025682 A025683 * A025685 A025686 A025687

Keyword

nonn,easy

Author

David W. Wilson

Status

approved