login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A186508
Number of lunar divisors (A087029) of the decimal numbers 1, 10, 11, 100, 101, 110, 111, 1000, ... .
0
9, 19, 90, 27, 90, 180, 819, 36, 90, 180, 738, 270, 738, 1638, 7641, 45, 90, 180, 738, 270, 819, 1476, 6570, 360, 738, 1476, 6732, 2457, 6570, 14922, 67968
OFFSET
1,1
COMMENTS
This is for lunar arithmetic in base 10.
LINKS
D. Applegate, M. LeBrun and N. J. A. Sloane, Dismal Arithmetic [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing]
EXAMPLE
The lunar divisors of 1 are 1,2,3,4,5,6,7,8,9, so a(1)=9.
The lunar divisors of 10 are 1...9 and 10, 20, 30, 40, ..., 90, so a(2) = 18.
CROSSREFS
KEYWORD
base,nonn,more
AUTHOR
N. J. A. Sloane, Feb 22 2011
STATUS
approved