|
Search: id:A119739
|
|
|
| A119739 |
|
Numbers n such that 7^n+3 is semiprime. |
|
+0
1
|
| |
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
Or (7^n+3)/2 is prime.
|
|
EXAMPLE
|
7^1+3=19=2*5,
7^3+3=346=2*173,
7^31+3=2*78887691017422903307521373,
7^47+3=2*2621669158378151817230729359430975727773,
7^83+3=2*6951960974910262341699296037696359556850100616048572362472005937832173
|
|
MATHEMATICA
|
Do[ If[ PrimeQ[(7^n + 3)/2], Print@n], {n, 1, 11501, 2}] (* Robert G. Wilson v *)
|
|
CROSSREFS
|
Sequence in context: A068331 A078330 A107210 this_sequence A163579 A141966 A050833
Adjacent sequences: A119736 A119737 A119738 this_sequence A119740 A119741 A119742
|
|
KEYWORD
|
more,nonn,less
|
|
AUTHOR
|
Zak Seidov (zakseidov(AT)yahoo.com), Jun 14 2006
|
|
EXTENSIONS
|
a(6) from Robert G. Wilson v (rgwv(at)rgwv.com), Jun 14 2006
|
|
|
Search completed in 0.002 seconds
|
