login
A051812
Number of n-digit numbers with nonzero multiplicative digital root 1.
1
1, 5, 24, 243, 3048, 35224, 374890, 3766188, 36537927, 348892847, 3315037530, 31399344551, 295789894509, 2769886220702, 25882768895688, 243033400452156
OFFSET
1,2
COMMENTS
Not counting zero as a one-digit number.
REFERENCES
William Mayne, sci.math, Jun 15 1991
FORMULA
a(n) = # { i : 10^(n-1) < i < 10^n and A051802(i)=1 }.
CROSSREFS
KEYWORD
nonn,base,hard
AUTHOR
Dan Hoey, Dec 09 1999
STATUS
approved