A088469 Number of distinct lunar prime divisors of n.

0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 17, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 15, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 13, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1

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

Table of n, a(n) for n=1..97.

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.

Index entries for sequences related to dismal (or lunar) arithmetic

Example

10 = 9*90 and 90 is prime. 90 is the only prime divisor of 10, so a(10) = 1.

Crossrefs

Cf. A088471, A088472, A087097.

Sequence in context: A241027 A176728 A300909 * A089170 A040292 A040293

Adjacent sequences: A088466 A088467 A088468 * A088470 A088471 A088472

Keyword

nonn

Author

David Applegate, Nov 11 2003

Status

approved