OFFSET
1,1
COMMENTS
Prime versus probable prime status and proofs are given in the author's table.
REFERENCES
C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
LINKS
Patrick De Geest, PDP Reference Table - 161.
Makoto Kamada, Prime numbers of the form 166...661.
FORMULA
a(n) = A056247(n+1) + 2.
EXAMPLE
k=13 -> (15*10^(13-1) - 51)/9 = 1666666666661.
PROG
(PARI) is(n)=ispseudoprime(2*(10^n-1)/3-5*(10^(n-1)+1)) || ispseudoprime(15*10^(n-1)-51)/9 \\ Charles R Greathouse IV, Feb 07 2013
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Patrick De Geest, Apr 13 2003
EXTENSIONS
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
Edited by Ray Chandler, Nov 04 2014
STATUS
approved