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A087636 Number of n-digit lunar primes. 5
0, 18, 81, 1539, 20457, 242217, 2894799, 33535839, 381591711 (list; graph; refs; listen; history; text; internal format)
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, N. J. A. Sloane, Dismal Arithmetic, J. Int. Seq. 14 (2011) # 11.9.8.

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,changed

AUTHOR

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

EXTENSIONS

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

STATUS

approved

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Last modified November 19 14:52 EST 2018. Contains 317352 sequences. (Running on oeis4.)