OFFSET
1,1
COMMENTS
Prime versus probable prime status and proofs are given in the author's table.
a(10) > 2^16. - Lucas A. Brown, Apr 18 2021
a(10) > 2*10^5. - Tyler Busby, Feb 01 2023
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 - 313.
Makoto Kamada, Prime numbers of the form 311...113.
FORMULA
a(n) = A056251(n) + 2.
EXAMPLE
k=15 -> (28*10^(15-1) + 17)/9 = 311111111111113.
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Patrick De Geest, Apr 13 2003
EXTENSIONS
Edited by Ray Chandler, Nov 04 2014
STATUS
approved