|
|
A102740
|
|
Numbers k such that 7*10^k - 11 is prime.
|
|
0
|
|
|
1, 6, 7, 9, 10, 11, 16, 42, 53, 78, 321, 699, 1858, 3425, 4899, 5734, 11081, 11675, 12136, 14056, 16074, 77969, 158465
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
a(24) > 2*10^5.
Numbers corresponding to terms <= 699 are certified primes. - Klaus Brockhaus, Feb 15 2005
For k>1, numbers such that the digit 6 followed by k-2 occurrences of the digit 9 followed by the digits 89 is prime (see Example section).
|
|
LINKS
|
|
|
EXAMPLE
|
Initial terms and primes associated:
a(1) = 1, 59;
a(2) = 6, 6999989;
a(3) = 7, 69999989;
a(4) = 9, 6999999989;
a(5) = 10, 69999999989; etc.
|
|
MATHEMATICA
|
Select[Range[1, 100000], PrimeQ[7*10^# - 11] &]
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
more,nonn
|
|
AUTHOR
|
Tom Mueller (muel4503(AT)uni-trier.de), Feb 08 2005
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|