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A088469 Number of distinct lunar prime divisors of n. 3
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 (list; graph; refs; listen; history; text; internal format)
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]

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: A144692 A241027 A176728 * A089170 A040292 A040293

Adjacent sequences:  A088466 A088467 A088468 * A088470 A088471 A088472

KEYWORD

nonn

AUTHOR

David Applegate, Nov 11 2003

STATUS

approved

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Last modified May 22 11:38 EDT 2017. Contains 286840 sequences.