|
Search: id:A147793
|
|
|
| A147793 |
|
Smallest prime q such that p^q-2 is prime where p ranges over the set of primes numbers. |
|
+0
1
|
|
| 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 3, 2, 2, 2, 2, 3, 2, 2, 2, 3, 149, 2, 5, 2, 7, 2, 2, 5, 2, 2, 3, 2, 5, 3, 89, 2, 2, 2, 13, 2, 3, 367, 2, 17, 3, 2, 2, 3, 2, 2, 2, 2, 439, 2, 61, 127, 2, 2, 3, 2, 37, 2, 3, 2, 2, 2, 2, 2, 2, 2
(list; graph; listen)
|
|
|
OFFSET
|
2,1
|
|
|
EXAMPLE
|
2^2-2 = 2 prime so a(1)=2, 3^2-2= 7 prime a(2)=2. For q=2,3,5, 199^q-2 is not
prime. For q=7, 199^7-2 = 12358664279161397 prime so a(27)=7.
|
|
PROGRAM
|
(PARI) g2(n) = forprime(x=2, n, y=g(1000, x); if(y>0, print1(y", ")))
g(n, m) = p1=0; forprime(p=2, n, y=m^p-2; if(ispseudoprime(y), p1=p; break)); p1
|
|
CROSSREFS
|
Sequence in context: A103795 A123627 A001991 this_sequence A052298 A081412 A082863
Adjacent sequences: A147790 A147791 A147792 this_sequence A147794 A147795 A147796
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Cino Hilliard (hillcino368(AT)hitmail.com), Nov 13 2008
|
|
|
Search completed in 0.002 seconds
|
