A051814 Number of n-digit numbers with nonzero multiplicative digital root 3.

1, 7, 40, 240, 1448, 8630, 53545, 371845, 3267453, 36428242, 442762543, 5217693527, 57321559329, 586532407659, 5666269188709, 52728701479194

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)=3 }

Crossrefs

Cf. A051802, A051805, A051823.

Sequence in context: A243875 A360101 A371813 * A154968 A121582 A239989

Adjacent sequences: A051811 A051812 A051813 * A051815 A051816 A051817

Keyword

nonn,base,hard

Author

Dan Hoey, Dec 09 1999

Status

approved