|
|
A275096
|
|
Numbers k such that 2*10^k + 89 is prime.
|
|
0
|
|
|
1, 3, 4, 8, 9, 10, 13, 20, 27, 74, 89, 93, 137, 139, 296, 310, 662, 749, 1249, 2540, 2848, 3309, 8677, 11573, 15286, 17125, 39526, 42187, 44476, 47823, 92897
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
For k > 1, numbers k such that the digit 2 followed by k-2 occurrences of the digit 0 followed by the digits 89 is prime (see Example section).
a(32) > 10^5.
|
|
LINKS
|
|
|
EXAMPLE
|
3 is in this sequence because 2*10^3 + 89 = 2089 is prime.
Initial terms and associated primes:
a(1) = 1, 109;
a(2) = 3, 2089;
a(3) = 4, 20089;
a(4) = 8, 200000089;
a(5) = 9, 2000000089, etc.
|
|
MATHEMATICA
|
Select[Range[0, 100000], PrimeQ[2*10^# + 89] &]
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,more
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|