OFFSET
1,11
COMMENTS
a(n) is the number of lunar primes p that are lunar divisors of n. (Multiplicity is not taken into account. Each prime is counted at most once.)
LINKS
D. Applegate, C program for lunar arithmetic and number theory [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing]
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]
D. Applegate, M. LeBrun, N. J. A. Sloane, Dismal Arithmetic, J. Int. Seq. 14 (2011) # 11.9.8.
EXAMPLE
10 = 9*90 and 90 is prime. 90 is the only prime divisor of 10, so a(10) = 1.
CROSSREFS
KEYWORD
nonn
AUTHOR
David Applegate, Nov 11 2003
STATUS
approved