A051816 Number of n-digit numbers with nonzero multiplicative digital root 5.

1, 7, 58, 422, 2872, 19772, 142418, 1096582, 9040811, 78452199, 699839588, 6297456806, 56804155533, 517737762700, 4839960759976, 46837953974511

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)=5 }

Crossrefs

Cf. A051802, A051807, A051825.

Sequence in context: A219974 A266051 A202975 * A015566 A238810 A362210

Adjacent sequences: A051813 A051814 A051815 * A051817 A051818 A051819

Keyword

nonn,base,hard

Author

Dan Hoey, Dec 09 1999

Status

approved