|
| |
|
|
A082704
|
|
Plateau and depression primes of the form (10^a(n)-1)/9+2*(10^[ a(n)-1 ]+1) or (28*10^[ a(n)-1 ]+17)/9.
|
|
2
|
| |
|
|
|
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
|
Table of n, a(n) for n=1..9.
Patrick De Geest, PDP Reference Table - 313.
Makoto Kamada, Prime numbers of the form 311...113.
Index entries for primes involving repunits.
|
|
|
FORMULA
|
a(n) = A056251(n) + 2.
|
|
|
EXAMPLE
|
a(n)=15 -> (10^15-1)/9+2*(10^14+1) = 311111111111113.
|
|
|
CROSSREFS
|
Cf. A082697-A082720, A056251, A068650.
Sequence in context: A113487 A032623 A146512 * A152270 A032919 A216044
Adjacent sequences: A082701 A082702 A082703 * A082705 A082706 A082707
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Patrick De Geest, Apr 13 2003.
|
|
|
EXTENSIONS
|
Edited by Ray Chandler, Nov 04 2014
|
|
|
STATUS
|
approved
|
| |
|
|
