A357526 Number of nonnegative integers less than n with the same product of the nonzero decimal digits as n.

0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 2, 2, 2, 0, 0, 0, 0, 0, 2, 3, 3, 2, 1, 0, 1, 0, 0, 0, 3, 4, 3, 2, 1, 0, 1, 0, 0, 0, 2, 3, 1, 1, 1, 0, 0, 0, 0, 0, 4, 5, 3, 2, 2, 1, 1, 0, 0, 0, 2, 3, 1, 1, 1, 1, 1, 0, 0, 0, 4, 5, 2, 3, 1, 1, 1, 1, 0, 0, 3

Offset

0,11

Links

Table of n, a(n) for n=0..90.

Ilya Gutkovskiy, Scatterplot of a(n) up to n=10000

Formula

a(n) = |{j < n : A051801(j) = A051801(n)}|.

Example

a(1) = 1 because A051801(1) = 1 and also A051801(0) = 1.
a(21) = 3 because A051801(21) = 2 and also A051801(2) = A051801(12) = A051801(20) = 2.

Mathematica

Table[Length[Select[Range[0, n - 1], Times @@ DeleteCases[IntegerDigits[#], 0] == Times @@ DeleteCases[IntegerDigits[n], 0] &]], {n, 0, 90}]

Crossrefs

Cf. A051801, A138471, A254524, A338505.

Sequence in context: A321895 A321899 A027870 * A070077 A337200 A337201

Adjacent sequences: A357523 A357524 A357525 * A357527 A357528 A357529

Keyword

nonn,base

Author

Ilya Gutkovskiy, Oct 02 2022

Status

approved