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A051827 Number of numbers below 10^n with nonzero multiplicative digital root 7. 1
1, 4, 18, 104, 770, 7188, 71267, 668712, 5784858, 46456730, 351209716, 2538926040, 17934291011, 128545882129, 994784980860, 8902285643456 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Conjectured o(10^n)
REFERENCES
William Mayne, sci.math, Jun 15 1991
LINKS
FORMULA
# { i : 10^(n-1) < i < 10^n and A051802(i)=7 }
CROSSREFS
Sequence in context: A349021 A316186 A231274 * A007711 A321278 A020114
KEYWORD
nonn,base,hard
AUTHOR
Dan Hoey, Dec 09 1999
STATUS
approved

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Last modified July 21 06:08 EDT 2024. Contains 374463 sequences. (Running on oeis4.)