A357526 - OEIS

%I #5 Oct 02 2022 13:45:43

%S 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,

%T 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,

%U 0,0,2,3,1,1,1,1,1,0,0,0,4,5,2,3,1,1,1,1,0,0,3

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

%H Ilya Gutkovskiy, <a href="/A357526/a357526.jpg">Scatterplot of a(n) up to n=10000</a>

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

%e a(1) = 1 because A051801(1) = 1 and also A051801(0) = 1.

%e a(21) = 3 because A051801(21) = 2 and also A051801(2) = A051801(12) = A051801(20) = 2.

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

%Y Cf. A051801, A138471, A254524, A338505.

%K nonn,base

%O 0,11

%A _Ilya Gutkovskiy_, Oct 02 2022