

A087636


Number of ndigit lunar primes.


7




OFFSET

1,2


COMMENTS

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


LINKS

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.


PROG

(PARI) A87636=[]; A087636(n)={while(#A87636<n, A87636=concat(A87636, 0)); !A87636[n] && A87636[n]=sum(k=10^(n1), 10^n1, is_A087097(k)); A87636[n]} \\ Store results in array A87636 to avoid recalculation.  M. F. Hasler, Nov 15 2018


CROSSREFS



KEYWORD

nonn,base,more


AUTHOR



EXTENSIONS



STATUS

approved



