A051824 Number of numbers below 10^n with nonzero multiplicative digital root 4.

1, 13, 118, 898, 6350, 46329, 382410, 3645765, 38163792, 410943130, 4368127170, 45097983418, 451960864264, 4431128837948, 42987600398290, 417247179973351

Offset

1,2

References

William Mayne, sci.math, Jun 15 1991

Links

Table of n, a(n) for n=1..16.

Formula

# { i : 10^(n-1) < i < 10^n and A051802(i)=4 }

Crossrefs

Cf. A051802, A051806, A051815.

Sequence in context: A022737 A016295 A225965 * A367244 A016285 A121086

Adjacent sequences: A051821 A051822 A051823 * A051825 A051826 A051827

Keyword

nonn,base,hard

Author

Dan Hoey, Dec 09 1999

Status

approved