A025668 Exponent of 7 (value of j) in n-th number of form 6^i*7^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, 0, 12, 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) = A214411(A025626(n)). - Amiram Eldar, Nov 08 2025

Mathematica

seq[lim_] := IntegerExponent[Flatten[Table[6^i*7^j, {i, 0, Log[6, lim]}, {j, 0, Log[7, lim/6^i]}]] // Sort, 7]; seq[10^12] (* Amiram Eldar, Nov 08 2025 *)

Crossrefs

Cf. A025626, A025660, A214411.

Sequence in context: A163351 A166352 A025690 * A373748 A048151 A025675

Adjacent sequences: A025665 A025666 A025667 * A025669 A025670 A025671

Keyword

nonn,easy

Author

David W. Wilson

Status

approved