A087636 Number of n-digit lunar primes.

0, 18, 81, 1539, 20457, 242217, 2894799, 33535839, 381591711

Offset

1,2

Comments

Although a(1) through a(6) are divisible by 9, a(7) is not.

Links

Table of n, a(n) for n=1..9.

D. Applegate, C program for lunar arithmetic and number theory

D. Applegate, M. LeBrun and N. J. A. Sloane, Dismal Arithmetic, arxiv:1107.1130 [math.NT], July 2011. [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, J. Int. Seq. 14 (2011) # 11.9.8.

Benjamin Baily, Justine Dell, Henry L. Fleischmann, Faye Jackson, Steven J. Miller, Ethan Pesikoff, and Luke Reifenberg, Irreducibility over the max-min semiring, arXiv:2111.09786 [math.CO], 2021.

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

Prog

(PARI) A87636=[]; A087636(n)={while(#A87636<n, A87636=concat(A87636, 0)); !A87636[n] && A87636[n]=sum(k=10^(n-1), 10^n-1, is_A087097(k)); A87636[n]} \\ Store results in array A87636 to avoid re-calculation. - M. F. Hasler, Nov 15 2018

Crossrefs

Cf. A087062 (lunar product), A087097 (lunar primes), A087638 (partial sums).

Sequence in context: A214531 A271502 A235641 * A156218 A118293 A043430

Adjacent sequences: A087633 A087634 A087635 * A087637 A087638 A087639

Keyword

nonn,base,more

Author

Marc LeBrun and N. J. A. Sloane, Oct 26 2003

Extensions

a(6)-a(9) from David Applegate, Nov 07 2003

Status

approved