A051821 Number of numbers below 10^n with nonzero multiplicative digital root 1 (not counting 0).

1, 6, 30, 273, 3321, 38545, 413435, 4179623, 40717550, 389610397, 3704647927, 35103992478, 330893886987, 3100780107689, 28983549003377, 272016949455533

Offset: 1

Author

Dan Hoey, Dec 09 1999

Keywords

• nonn
• base
• hard

References

• William Mayne, sci.math, Jun 15 1991

Crossrefs

Cf. A051802, A051803, A051812.

Formula

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