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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
1, 2, 3, 4, 5, 6, 7, 8, 90 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 19 22:00 EDT 2018. Contains 316378 sequences. (Running on oeis4.)