|
Search: id:A083388
|
|
|
| A083388 |
|
a(n) = beginning of a run of n primes when x -> 3*x + 2 is iterated. |
|
+0
9
|
| |
|
|
OFFSET
|
1,1
|
|
|
REFERENCES
|
D. H. Lehmer, On certain chains of primes, Proc. London Math. Soc. (3) 14a 1965 183-186.
|
|
EXAMPLE
|
a(3) = 5 because 5 is the beginning of 3 primes in succession: 5, 3*5+2=17 is prime, and 3*17+2=53 is prime.
|
|
PROGRAM
|
(PARI) mx=1; forprime(p=1, 198000, x=p; m=0; while(isprime(x=3*x+2), m=m+1; if(m>mx, print(p, " ", m, " ", x); mx=m, )))
|
|
CROSSREFS
|
Cf. A057331, A081173.
Sequence in context: A093490 A073309 A110389 this_sequence A090475 A060301 A040119
Adjacent sequences: A083385 A083386 A083387 this_sequence A083389 A083390 A083391
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Edwin Clark (eclark(AT)math.usf.edu), Jun 09 2003
|
|
EXTENSIONS
|
Pari program from Donald S. McDonald (don.mcdonald(AT)paradise.net.nz), Jun 11 2003
|
|
|
Search completed in 0.002 seconds
|
