|
|
A272059
|
|
Numbers k such that (17*10^k + 13)/3 is prime.
|
|
0
|
|
|
1, 2, 4, 7, 10, 13, 15, 20, 22, 33, 34, 108, 117, 130, 193, 273, 280, 654, 775, 1144, 4014, 4015, 7701, 10356, 11478, 12427, 15075, 44107, 102597, 118635
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
For k>1, numbers n such that the digit 5 followed by k-2 occurrences of the digit 6 followed by the digits 71 is prime (see Example section).
a(31) > 2*10^5.
|
|
LINKS
|
|
|
EXAMPLE
|
4 is in this sequence because (17*10^4 + 13)/3 = 56671 is prime.
Initial terms and primes associated:
a(1) = 1, 61;
a(2) = 2, 571:
a(3) = 4, 56671;
a(4) = 7, 56666671;
a(5) = 10, 56666666671, etc.
|
|
MATHEMATICA
|
Select[Range[0, 100000], PrimeQ[(17*10^# + 13)/3] &]
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,more
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|