

A109752


Using the lunar product (see A087062 for definition), numbers n such that if n divides a*b, then n must divide either a or b. The multiplicative identity, 9, is excluded by convention.


0




OFFSET

1,2


COMMENTS

This condition is one of the definitions of a prime, so these numbers could be called lunar primes (cf. A087097).


LINKS

Table of n, a(n) for n=1..9.
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]
Index entries for sequences related to dismal (or lunar) arithmetic


EXAMPLE

90 is a member because the lunar multiples of 90 are the same as the numbers ending with a 0 and if neither a nor b ends in 0, then neither does a*b.


CROSSREFS

Cf. A087062, A087097.
Sequence in context: A043313 A171679 A044910 * A098755 A028430 A290148
Adjacent sequences: A109749 A109750 A109751 * A109753 A109754 A109755


KEYWORD

base,fini,full,nonn,less


AUTHOR

David Wasserman, Aug 11 2005


STATUS

approved



