login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A051815 Number of n-digit numbers with nonzero multiplicative digital root 4. 1
1, 12, 105, 780, 5452, 39979, 336081, 3263355, 34518027, 372779338, 3957184040, 40729856248, 406862880846, 3979167973684, 38556471560342, 374259579575061 (list; graph; refs; listen; history; text; internal format)
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)=4 }

CROSSREFS

Cf. A051802, A051806, A051824.

Sequence in context: A220111 A094530 A157024 * A004321 A016223 A027142

Adjacent sequences:  A051812 A051813 A051814 * A051816 A051817 A051818

KEYWORD

nonn,base,hard

AUTHOR

Dan Hoey, Dec 09 1999

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 23 23:51 EDT 2019. Contains 328379 sequences. (Running on oeis4.)