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
Examples
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.
Links
- Ilya Gutkovskiy, Scatterplot of a(n) up to n=10000
Programs
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Mathematica
Table[Length[Select[Range[0, n - 1], Times @@ DeleteCases[IntegerDigits[#], 0] == Times @@ DeleteCases[IntegerDigits[n], 0] &]], {n, 0, 90}]